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What exactly is LLVM?
LLVM is an acronym that stands for low level virtual machine. It also refers to a compiling technology called the LLVM project, which is a collection of modular and reusable compiler and toolchain technologies.
What does LLVM compile to?
LLVM currently supports compiling of Ada, C, C++, D, Delphi, Fortran, Haskell, Julia, Objective-C, Rust, and Swift using various front ends. Widespread interest in LLVM has led to several efforts to develop new front ends for a variety of languages.
Why is LLVM so big?
A full build of LLVM and Clang will need around 15-20 GB of disk space. The exact space requirements will vary by system. (It is so large because of all the debugging information and the fact that the libraries are statically linked into multiple tools).
Who uses LLVM?
Apple’s Swift language uses LLVM as its compiler framework, and Rust uses LLVM as a core component of its tool chain. Also, many compilers have an LLVM edition, such as Clang, the C/C++ compiler (this the name, “C-lang”), itself a project closely allied with LLVM.
Where is LLVM used?
7 Answers. LLVM is a library that is used to construct, optimize and produce intermediate and/or binary machine code. LLVM can be used as a compiler framework, where you provide the “front end” (parser and lexer) and the “back end” (code that converts LLVM’s representation to actual machine code).
Why does Apple use LLVM?
Multiple technology groups within Apple are active contributors within the LLVM.org community, and they use LLVM technology to make Apple platforms faster and more secure.
Where is Clang used?
The Clang tool is a front end compiler that is used to compile programming languages such as C++, C, Objective C++ and Objective C into machine code. Clang is also used as a compiler for frameworks like OpenMP, OpenCL, RenderScript, CUDA and HIP.
Should I use GCC or clang?
Clang is much faster and uses far less memory than GCC. Clang aims to provide extremely clear and concise diagnostics (error and warning messages), and includes support for expressive diagnostics. GCC’s warnings are sometimes acceptable, but are often confusing and it does not support expressive diagnostics.
What makes LLVM a low level programming language?
The core of LLVM is the intermediate representation (IR), a low-level programming language similar to assembly. IR is a strongly typed reduced instruction set computing (RISC) instruction set which abstracts away most details of the target. For example, the calling convention is abstracted through call and ret instructions with explicit arguments.
How did the LLVM project get its name?
The LLVM project started with an IR that operated at a lower level than the Java bytecode, thus, the initial acronym was Low Level Virtual Machine. The idea was to explore low-level optimization opportunities and employ link-time optimizations. The link-time optimizations were made possible by writing the IR to disk, as in a bytecode.
What kind of instruction set does LLVM support?
LLVM supports a language-independent instruction set and type system. Each instruction is in static single assignment form (SSA), meaning that each variable (called a typed register) is assigned once and then frozen.
Which is an equivalent form of the LLVM IR?
The LLVM project started as a set of tools that orbit around the LLVM IR, which justifies the maturity of the optimizers and the number of optimizers that act at this level. This IR has three equivalent forms: An in-memory representation (the Instruction class, among others)