LLVM
llvm.org › docs › LangRef.html
LLVM Language Reference Manual — LLVM 23.0.0git documentation
May 12, 2026 - The compiler may assume that a ... generated even if the definition is not within this compilation unit. LLVM IR allows you to specify both “identified” and “literal” structure types....
mcyoung
mcyoung.xyz › 2023 › 08 › 01 › llvm-ir
A Gentle Introduction to LLVM IR · mcyoung
LLVM IR is a static single assignment form (SSA) IR. LLVM was actually started at the turn of the century to create a modern SSA optimizer as an academic project. These days, SSA is extremely fashionable for optimizing imperative code.
Is it possible to do runtime compilation and execution of C code?
LLVM IR isn’t designed to be executable, it’s designed to be translated to machine code. but you can probably use libclang to compile a file to a DLL and then load it without using the disk (e.g. using https://github.com/fancycode/MemoryModule on Windows). if you can’t avoid using the disk for any of the steps, just use temporary files More on reddit.com
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December 11, 2023Challenges writing a compiler frontend targeting both LLVM and GCC?
That sounds really hard. Writing a compiler frontend is hard enough. Writing one which interacts correctly and efficiently with two very different middles seems just masochistic. What do you hope to gain by this and is it worth it? Have you considered just writing an independent source-to-source transformer the output of which can be fed automatically into the regular GCC/LLVM frontend? More on reddit.com
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March 7, 2023Adding an intrinsic function to LLVM
Take a look at https://reviews.llvm.org/D139883 for an example. More on reddit.com
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February 3, 2023Inlining functions that will only ever be called once - is this a good convention?
I'm not an expert on the rustc compiler internals, but I would recommend against this, for the simple reason that the compiler knows better. Modern compilers, particularly LLVM-based compilers, are extraordinarily well equipped to make this determination themselves. [inline(always)] is for moments when you, the programmer, genuinely know something that the compiler doesn't. If it will result in smaller and faster code, you can be well assured that rustc will auto-inline your functions. And in the example you describe, I would imagine that it does. (You can always examine the output asm to see whether this is the case; I think it would be interesting for you to share those findings if you feel obliged.) More on reddit.com
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July 13, 2022Videos
LLVM
llvm.org › doxygen › classllvm_1_1Function.html
LLVM: llvm::Function Class Reference
Referenced by llvm::CanInlineC... as the profiled optimized binary. Definition at line 1131 of file Function.cpp. Returns the number of non-debug IR instructions in this function....
LLVM
releases.llvm.org › 2.6 › docs › tutorial › JITTutorial1.html
LLVM Tutorial 1: A First Function
October 24, 2009 - But what good is a function if it has no body? Before we start working on a body for our new function, we need to recall some details of the LLVM IR. The IR, being an abstract assembly language, represents control flow using jumps (we call them branches), both conditional and unconditional.
USNA
usna.edu › Users › cs › wcbrown › courses › F19SI413 › lab › l13 › lab.html
SI413: Compilingto LLVM IR
The most important types you will need to use in LLVM IR are: i1: This is a 1-bit integer, i.e., a boolean value. This is the type returned by comparison instructions in LLVM, and it is the type that you must use for the condition of conditional branches. i8: An 8-bit integer, i.e., a char. You have to use this type when calling system functions like printf which expect (arrays of) characters.
/undevs
un-devs.github.io › home › low level exploration
A Journey to understand LLVM-IR! - /undevs
July 16, 2021 - I would suggest you to get a free ... = %start ret i64 %1}The next interesting function to look at is the @_ZN4main4main17h2d6c3d678af9e020E function which the LLVM-IR dump equivalent to our original main function of this program :; main::main; Function Attrs: nonlazybind ...
LLVM
llvm.org › docs › tutorial › MyFirstLanguageFrontend › LangImpl03.html
3. Kaleidoscope: Code generation to LLVM IR — LLVM 23.0.0git documentation
It then uses the Functiontype::get method to create a function type that takes “N” doubles as arguments, returns one double as a result, and that is not vararg (the false parameter indicates this). Note that Types in LLVM are uniqued just like Constants are, so you don’t “new” a type, you “get” it. The final line above actually creates the IR Function corresponding to the Prototype.
Readthedocs
mapping-high-level-constructs-to-llvm-ir.readthedocs.io › en › latest › basic-constructs › functions.html
Function Definitions and Declarations — Mapping High Level Constructs to LLVM IR documentation
Function overloading is actually not dealt with on the level of LLVM IR, but on the source language. Function names are mangled, so that they encode the types they take as parameter and return in their function name.
LLVM
releases.llvm.org › 11.0.0 › docs › LangRef.html
LLVM Language Reference Manual — LLVM 11 documentation
The compiler may assume that a ... generated even if the definition is not within this compilation unit. LLVM IR allows you to specify both “identified” and “literal” structure types....
AMD ROCm
rocm.docs.amd.com › projects › llvm-project › en › latest › LLVM › llvm › html › LangRef.html
LLVM Language Reference Manual — LLVM 22.0.0git documentation
The compiler may assume that a ... generated even if the definition is not within this compilation unit. LLVM IR allows you to specify both “identified” and “literal” structure types....
Mukulrathi
mukulrathi.com › blog › a complete guide to llvm for programming language creators
A Complete Guide to LLVM for Programming Language Creators
December 24, 2020 - So in short: LLVM IR looks like assembly with types, minus the messy machine-specific details. LLVM IR must be in SSA form, which makes it easier to optimise. Let’s look at an example! Let’s look at a simple factorial function in our language Bolt:
Readthedocs
llvmlite.readthedocs.io › en › latest › user-guide › ir › examples.html
Example—defining a simple function — llvmlite 0.49.0dev0+18.g6302ab2.dirty documentation
April 30, 2026 - module = ir.Module(name=__file__) # and declare a function named "fpadd" inside it func = ir.Function(module, fnty, name="fpadd") # Now implement the function block = func.append_basic_block(name="entry") builder = ir.IRBuilder(block) a, b = func.args result = builder.fadd(a, b, name="res") builder.ret(result) # Print the module IR print(module) The generated LLVM intermediate representation is printed at the end:
Read the Docs
media.readthedocs.org › pdf › mapping-high-level-constructs-to-llvm-ir › latest › mapping-high-level-constructs-to-llvm-ir.pdf pdf
Mapping High Level Constructs to LLVM IR Documentation Test Sep 10, 2023
Similar to low-level assembly languages, LLVM’s IR consists of sequences of instructions, that are executed sequen- tially. The instructions are grouped together to form basic blocks. Each basic block terminates with an instruction that ... First let’s take a look at a very simple function, ...
Medium
medium.com › @mlshark › introduction-to-llvm-syntax-06a262f762eb
An Introduction to LLVM Syntax. What is LLVM | by Allen Liang | Dec, 2024 | Medium
December 19, 2024 - In LLVM IR, all variables are prefixed with % for local variables or @ for global ones. Also, all the variables comply with the SSA (Static Single Assignment) form, meaning each variable is assigned a value exactly once.
LLVM
llvm.org › docs › MIRLangRef.html
Machine IR (MIR) Format Reference Manual — LLVM 23.0.0git documentation
When the first YAML document contains a YAML block literal string, the MIR parser will treat this string as an LLVM assembly language string that represents an embedded LLVM IR module. Here is an example of a YAML document that contains an LLVM module: define i32 @inc(ptr %x) { entry: %0 = load i32, ptr %x %1 = add i32 %0, 1 store i32 %1, ptr %x ret i32 %1 } The remaining YAML documents contain the machine functions.
Skenz
skenz.it › compilers › llvm
compilers:llvm [Skenz - How To Wiki]
April 8, 2024 - This module transforms the IR, applying some analysis, optimizations and transformations. The back-end takes the Itermediate Representation optimized by the middle-end, and generates the native code for a given machine, like ARM, MIPS, Intel, Sparc, etc., ready to be executed by the target machine. The intermediate representation LLVM (IR) is independent from both the language and the architecture; it is placed between the source code in a given programming language and the machine code for a specific architecture...
MLIR
mlir.llvm.org › docs › Tutorials › UnderstandingTheIRStructure
Understanding the IR Structure - MLIR - LLVM
For example the following walk will find all AllocOp nested inside the function and interrupt the traversal if one of them does not satisfy a criteria: WalkResult result = getFunction().walk([&](AllocOp allocOp) { if (!isValid(allocOp)) return WalkResult::interrupt(); return WalkResult::advance(); }); if (result.wasInterrupted()) // One alloc wasn't matching. ... Another relationship in the IR is the one that links a Value with its users.
AMD ROCm
rocm.docs.amd.com › projects › llvm-project › en › latest › LLVM › llvm › html › tutorial › MyFirstLanguageFrontend › LangImpl03.html
3. Kaleidoscope: Code generation to LLVM IR — LLVM 20.0.0git documentation
This step isn’t strictly necessary, but keeping the names consistent makes the IR more readable, and allows subsequent code to refer directly to the arguments for their names, rather than having to look up them up in the Prototype AST. At this point we have a function prototype with no body. This is how LLVM IR represents function declarations.
Gopher Academy Blog
blog.gopheracademy.com › advent-2018 › llvm-ir-and-go
LLVM IR and Go | Gopher Academy Blog
December 20, 2018 - 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.
Freemasen
freemasen.com › blog › llvm-ir
LLVM IR - Free Masen
December 16, 2023 - While llvm-ir doesn't have a string type, it does have a nice way to create an array of bytes using the c"..." syntax, in our example we are defining a 14 byte array because Hello World! is 12 bytes and then we need to add the \0A (\n) and \00 (NUL) bytes to the end, which is what printf will expect. With that out of the way, let's update our @main function to use these two new additions.