The LLVM representation aims to be light-weight and low-level while being expressive, typed, and extensible at the same time. It aims to be a “universal IR” of sorts, by being at a low enough level that high-level ideas may be cleanly mapped to it (similar to how microprocessors are “universal IR’s”, allowing many source languages to be mapped to them).

LLVM often also refers to just the optimizer and backend parts of Clang; this is can be thought of as a compiler for the “LLVM language” or “LLVM assembly”. Clang, and other language frontends like Rust, essentially compile to LLVM IR, which LLVM then compiles to machine code.

In your question, you are probably referring to LLVM IR, where IR stands for "intermediate representation". The IR is used from most compilers to create a language that is close to assembly but not so low yet.

LLVM can provide the middle layers of a complete compiler system, taking intermediate representation (IR) code from a compiler and emitting an optimized IR. This new IR can then be converted and linked into machine-dependent assembly language ...

For example, there may be something like attributes #0 = { alwaysinline alignstack=4 } in the IR, and these attributes will be applied to main. ... This allocates a 32 bit integer on the stack. %1 is the name of a pointer to this location on the stack. The align 4 ensures that the address will be a multiple of 4 ... This sets the 32 bit integer pointed to by %1 to the 32 bit value 0. It's like saying *x = 1 in C++ ... The assignment is odd, considering that you don't have a local variable in main. LLVM uses BasicBlock to represent groups of instructions, and a basic block has an exit point and a list of instructions.

The LLVM Project is a collection of modular and reusable compiler and toolchain technologies. Despite its name, LLVM has little to do with traditional virtual machines. The name "LLVM" itself is not an acronym; it is the full name of the project · LLVM began as a research project at the University ...

The equivalent LLVM-IR is way more large and bloated compared to that of C, but we have a lot of new functions here we will focus on only those important functions, I will be taking the help of a disassembler to understand which are the functions might be of our interest!

Compilation, specially of the type of language LLVM is most used for (impure, procedural, object oriented, with optional collection) lend themselves to very similar optimization techniques. Optimization happens in phases, one after the other, sometimes a phase might need to be repeated after ...

LLVM IR is not machine code, but sort of the step just above assembly. So some things look more like a high-level language (like functions and the strong typing). Other looks more like low-level assembly (e.g.

; This is a sample program in LLVM IR @global_var = global i32 0 define i32 @main(i1 %cond) { br i1 %cond, label %then_block, label %else_block then_block: %x1 = add i32 0, 10 br label %merge_block else_block: %x2 = add i32 0, 20 br label %merge_block merge_block: %x = phi i32 [ %x1, %then_block ], [ %x2, %else_block ] %y = add i32 %x, 5 ret i32 0 }

In this post, we’ll look at how to build Go programs – such as compilers and static analysis tools – that interact with the LLVM compiler framework using the LLVM IR assembly language.

Extension for Visual Studio Code - LLVM IR language support for Visual Studio Code

In this email, I argue that LLVM IR is a poor system for building a Platform, by which I mean any system where LLVM IR would be a format in which programs are stored or transmitted for subsequent use on multiple underlying architectures.

For a project I need to obtain the LLVM IR emitted by the Swift compiler, instrument it and run it. For that, I want to use either clang or llvms llc. However when I execute the program I get a segmentation fault and I h…

The codegen() method says to emit IR for that AST node along with all the things it depends on, and they all return an LLVM Value object. “Value” is the class used to represent a “Static Single Assignment (SSA) register” or “SSA value” in LLVM. The most distinct aspect of SSA values is that their value is computed as the related instruction executes, and it does not get a new value until (and if) the instruction re-executes.

LLVM IR was chosen as an appropriate form to write compiler optimisations. As such, it's primary feature is that it's in SSA form. It's quite a low level IR so that it is applicable to a wide range of languages e.g.

LLVM IR is also binary format (sometimes called “bitcode”), although we will be working exclusively with its text format (which uses the .ll extension).

Modern Intermediate Representations (IR) David Chisnall · University of Cambridge · LLVM Summer School, Paris, June 12, 2017 · Reusable IR · • Modern compilers are made from loosely coupled components · • Front ends produce IR · • Middle ‘ends’ transform IR (optimisation / analysis / instrumentation) • Back ends generate native code (object code or assembly) Structure of a Modern Compiler ·

LLVM IR in natural Rust data structures. Contribute to cdisselkoen/llvm-ir development by creating an account on GitHub.

Lack of freedom: If you use LLVM as an IR you're practically required to adhere to LLVM conventions: e.g. Module/Function/BB/Instruction, using ...Builders like IRBuilder to construct values, using llvm Types and Values and Metadata.