LLVM IR - Intermediate representation language

LLVM IR is an open source intermediate representation language created in 2003.

#71on PLDB

21Years Old

1kRepos

Homepage · REPL · Try It Online · Download · Blog · Wikipedia · FAQ · Release Notes · Docs

The LLVM compiler infrastructure project is a "collection of modular and reusable compiler and toolchain technologies" used to develop compiler front ends and back ends. LLVM is written in C++ and is designed for compile-time, link-time, run-time, and "idle-time" optimization of programs written in arbitrary programming languages. Originally implemented for C and C++, the language-agnostic design of LLVM has since spawned a wide variety of front ends: languages with compilers that use LLVM include ActionScript, Ada, C#, Common Lisp, Crystal, D, Delphi, Fortran, OpenGL Shading Language, Halide, Haskell, Java bytecode, Julia, Lua, Objective-C, Pony, Python, R, Ruby, Rust, CUDA, Scala, Swift, and Xojo. Read more on Wikipedia...

Tags: intermediate representation language
There are at least 1,351 LLVM IR repos on GitHub
Early development of LLVM IR happened in https://github.com/llvm
The Google BigQuery Public Dataset GitHub snapshot shows 1k users using LLVM IR in 1k repos on GitHub
LLVM IR Ubuntu package
Pygments supports syntax highlighting for LLVM IR
LLVM IR appears in the Quine Relay project
Events page for LLVM IR
See also: (41 related languages) C, ActionScript, Ada, C#, Common Lisp, Crystal, D, Delphi, Fortran, GLSL, Haskell, Java Bytecode, Julia, Lua, Objective-C, Python, R, Ruby, Rust, CUDA, Scala, Swift, Xojo, iOS, Assembly language, Java, OpenGL, CIL, Standard ML, ARM, Qualcomm Hexagon, MIPS architecture, PTX, PowerPC, SPARC, X86, Extensible Linking Format, C--, Pure, OpenCL, ISBN
22 PLDB concepts link to LLVM IR: CIR, cloc, Emscripten, firrtl, FLEX, Halide, HHVM, invokator, Julia, Kotlin, neeilang, oopsilon, Pony, rhine, Rust MIR, Simit, sixten, souper, SIL, Swift, TensorFlow, Triton

Example from Compiler Explorer:

define i32 @square(i32) local_unnamed_addr #0 {
    %2 = mul nsw i32 %0, %0
    ret i32 %2
}

Example from Riju:

@.str = private unnamed_addr constant [13 x i8] c"Hello, world!"

declare i32 @puts(i8* nocapture) nounwind

define i32 @main() {
    %cast210 = getelementptr [13 x i8],[13 x i8]* @.str, i64 0, i64 0
    call i32 @puts(i8* %cast210)
    ret i32 0
}

Example from hello-world:

target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
@.str = internal constant [12 x i8] c"Hello World\00"

; puts from libc
declare i32 @puts(i8*)

define i32 @main(...) {
	call i32 @puts(i8* getelementptr([12 x i8]* @.str, i32 0, i32 0))
	ret i32 0
}

Example from Wikipedia:

@.str = internal constant [14 x i8] c"hello, world\0A\00"

declare i32 @printf(i8*, ...)

define i32 @main(i32 %argc, i8** %argv) nounwind {
entry:
    %tmp1 = getelementptr [14 x i8], [14 x i8]* @.str, i32 0, i32 0
    %tmp2 = call i32 (i8*, ...) @printf( i8* %tmp1 ) nounwind
    ret i32 0
}

Language features

Feature	Supported	Example	Token
Comments	✓	; A comment
Line Comments	✓	; A comment	;
Semantic Indentation	X