1083 lines
31 KiB
Org Mode
1083 lines
31 KiB
Org Mode
#+TITLE: How to build a compiler with LLVM and MLIR
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#+SEQ_TODO: TODO(t/!) NEXT(n/!) BLOCKED(b@/!) | DONE(d%) CANCELLED(c@/!) FAILED(f@/!)
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#+TAGS: READER(r) MISC(m)
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#+STARTUP: logdrawer logdone logreschedule indent content align constSI entitiespretty overview
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* DONE Episode 1 - Introduction
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** What is it all about?
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- Create a programming lang
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- Guide for contributors
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- A LLVM/MLIR guide
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** The Plan
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- Git branches
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- No live coding
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- Feel free to contribute
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** Serene and a bit of history
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- Other Implementations
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- Requirements
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- C++ 14
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- CMake
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- Repository: https://devheroes.codes/Serene
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- Website: lxsameer.com
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Email: lxsameer@gnu.org
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* DONE Episode 2 - Basic Setup
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CLOSED: [2021-07-10 Sat 09:04]
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** Installing Requirements
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*** LLVM and Clang
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- mlir-tblgen
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*** ccache (optional)
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** Building Serene and the =builder=
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- git hooks
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** Source tree structure
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** =dev.org= resources and TODOs
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* DONE Episode 3 - Overview
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CLOSED: [2021-07-19 Mon 09:41]
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** Generic Compiler
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- [[https://www.cs.princeton.edu/~appel/modern/ml/whichver.html][Modern Compiler Implementation in ML: Basic Techniques]]
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- [[https://suif.stanford.edu/dragonbook/][Compilers: Principles, Techniques, and Tools (The Dragon Book)]]
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*** Common Steps
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- Frontend
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- Lexical analyzer (Lexer)
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- Syntax analyzer (Parser)
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- Semantic analyzer
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- Middleend
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- Intermediate code generation
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- Code optimizer
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- Backend
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- Target code generation
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** LLVM
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[[llvm.org]]
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*** Watch [[https://www.youtube.com/watch?v=J5xExRGaIIY][Introdution to LLVM]]
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*** Quick overview
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Deducted from https://www.aosabook.org/en/llvm.html
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[[./imgs/llvm_dia.svg]]
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- It's a set of libraries to create a compiler.
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- Well engineered.
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- we can focus only on the fronted of the compiler and what is
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actually important to us and leave the tricky stuff to LLVM.
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- LLVM IR enables us to use multiple languages together.
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- It supports many targets.
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- We can benefit from already made IR level optimizers.
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- ....
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** MLIR
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[[mlir.llvm.org]]
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[[./imgs/mlir_dia.svg]]
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- With MLIR dialects provide higher level semantics than LLVM IR.
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- It's easier to reason about higher level IR that is modeled after
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the AST rather than a low level IR.
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- We can use the pass infrastructure to efficiently process and transform the IR.
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- With many ready to use dialects we can really focus on our language and us the other
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dialect when ever necessary.
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- ...
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** Serene
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*** A Compiler frontend
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*** Flow
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- =serenec= in parses the command lines args
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- =reader= reads the input file and generates an =AST=
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- =semantic analyzer= walks the =AST= and generates a new =AST= and rewrites
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the necessary nodes.
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- =slir= generator generates =slir= dialect code from =AST=.
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- We lower =slir= to other dialects of the *MLIR* which we call the result =mlir=.
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- Then, We lower everything to the =LLVMIR dialect= and call it =lir= (lowered IR).
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- Finally we fully lower =lir= to =LLVM IR= and pass it to the object generator
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to generate object files.
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- Call the default =c compiler= to link the object files and generate the machine code.
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* DONE Episode 4 - The reader
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CLOSED: [2021-07-27 Tue 22:50]
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** What is a Parser ?
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To put it simply, Parser converts the source code to an [[https://en.wikipedia.org/wiki/Abstract_syntax_tree][AST]]
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*** Algorithms
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- LL(k)
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- LR
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- LALR
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- PEG
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- .....
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Read More:
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- https://stereobooster.com/posts/an-overview-of-parsing-algorithms/
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- https://tomassetti.me/guide-parsing-algorithms-terminology/
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*** Libraries
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- https://en.wikipedia.org/wiki/Comparison_of_parser_generators
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*** Our Parser
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- We have a hand written LL(1.5) like parser/lexer since lisp already has a structure.
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#+BEGIN_SRC lisp
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;; pseudo code
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(def some-fn (fn (x y)
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(+ x y)))
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(defn main ()
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(println "Result: " (some-fn 3 8)))
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#+END_SRC
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- LL(1.5)?
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- O(n)
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* DONE Episode 5 - The Abstract Syntax Tree
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CLOSED: [2021-07-30 Fri 14:01]
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** What is an AST?
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Ast is a tree representation of the abstract syntactic structure of source code. It's just a tree made of nodes that each node is
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a data structure describing the syntax.
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#+BEGIN_SRC lisp
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;; pseudo code
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(def main (fn () 4))
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(prn (main))
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#+END_SRC
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[[./imgs/ast.svg]]
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** The =Expression= abstract class
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*** Expressions
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- Expressions vs Statements
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- Serene(Lisp) and expressions
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** Node & AST
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* DONE Episode 6 - The Semantic Analyzer
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CLOSED: [2021-08-21 Sat 18:44]
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** Qs
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- Why didn't we implement a linked list?
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- Why we are using the =std::vector= instead of llvm collections?
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** What is Semantic Analysis?
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- Semantic Analysis makes sure that the given program is semantically correct.
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- Type checkr works as part of this step as well.
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#+BEGIN_SRC lisp
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;; pseudo code
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(4 main)
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#+END_SRC
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[[./imgs/incorrct_semantic.svg]]
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** Semantic Analysis and rewrites
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We need to reform the AST to reflect the semantics of Serene closly.
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#+BEGIN_SRC lisp
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;; pseudo code
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(def main (fn () 4))
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(prn (main))
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#+END_SRC
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[[./imgs/ast.svg]]
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[[./imgs/semantic.svg]]
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Let's run the compiler to see the semantic analysis in action.
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** Let's check out the code
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* DONE Episode 7 - The Context and Namespace
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CLOSED: [2021-09-04 Sat 10:53]
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** Namespaces
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*** Unit of compilation
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*** Usually maps to a file
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*** keeps the state and evironment
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** SereneContext vs LLVM Context vs MLIR Context
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*** Compilers global state
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*** The owner of LLVM/MLIR contexts
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*** Holds the namespace table
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*** Probably will contain the primitive types as well
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* DONE Episode 8 - MLIR Basics
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CLOSED: [2021-09-17 Fri 10:18]
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** Serene Changes
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- Introducing a SourceManager
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- Reader changes
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- *serenec* cli interface in changing
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** Disclaimer
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*I'm not an expert in MLIR*
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** Why?
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- A bit of history
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- LLVM IR is to low level
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- We need an IR to implement high level concepts and flows *MLIR* is a framework to build a compiler with your own IR. kinda :P
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- Reusability
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- ...
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** Language
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*** Overview
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- SSA Based (https://en.wikipedia.org/wiki/Static_single_assignment_form)
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- Typed
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- Context free(for lack of better words)
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*** Dialects
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- A collection of operations
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- Custom types
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- Meta data
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- We can use a mixture of different dialects
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**** builtin dialects:
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- std
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- llvm
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- math
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- async
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- ...
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*** Opetations
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- Higher level of abstraction
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- Not instructions
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- SSA forms
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- Tablegen backend
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- Verifiers and printers
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*** Attributes
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*** Blocks & Regions
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*** Types
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- Extesible
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** Pass Infrastructure
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Analysis and transformation infrastructure
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- We will implement most of our semantic analysis logic and type checker as passes
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** Pattern Rewriting
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- Tablegen backed
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** Operation Definition Specification
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** Examples
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*Not*: You need =mlir-mode= and =llvm-mode= available to you for the code highlighting of
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the following code blocks. Both of those are distributed with the LLVM.
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*** General syntax
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#+BEGIN_SRC mlir
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%result:2 = "somedialect.blah"(%x#2) { some.attribute = true, other_attribute = 3 }
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: (!somedialect<"example_type">) -> (!somedialect<"foo_s">, i8)
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loc(callsite("main" at "main.srn":10:8))
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#+END_SRC
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*** Blocks and Regions
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#+BEGIN_SRC mlir
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func @simple(i64, i1) -> i64 {
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^bb0(%a: i64, %cond: i1): // Code dominated by ^bb0 may refer to %a
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cond_br %cond, ^bb1, ^bb2
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^bb1:
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br ^bb3(%a: i64) // Branch passes %a as the argument
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^bb2:
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%b = addi %a, %a : i64
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br ^bb3(%b: i64) // Branch passes %b as the argument
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// ^bb3 receives an argument, named %c, from predecessors
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// and passes it on to bb4 along with %a. %a is referenced
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// directly from its defining operation and is not passed through
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// an argument of ^bb3.
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^bb3(%c: i64):
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//br ^bb4(%c, %a : i64, i64)
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"serene.ifop"(%c) ({ // if %a is in-scope in the containing region...
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// then %a is in-scope here too.
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%new_value = "another_op"(%c) : (i64) -> (i64)
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^someblock(%new_value):
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%x = "some_other_op"() {value = 4 : i64} : () -> i64
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}) : (i64) -> (i64)
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^bb4(%d : i64, %e : i64):
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%0 = addi %d, %e : i64
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return %0 : i64 // Return is also a terminator.
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}
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#+END_SRC
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*** SLIR example
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Command line arguments to emir =slir=
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#+BEGIN_SRC sh
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./builder run --build-dir ./build -emit slir `pwd`/docs/examples/hello_world.srn
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#+END_SRC
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Output:
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#+BEGIN_SRC mlir
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module @user {
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%0 = "serene.fn"() ( {
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%2 = "serene.value"() {value = 0 : i64} : () -> i64
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return %2 : i64
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}) {args = {}, name = "main", sym_visibility = "public"} : () -> i64
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%1 = "serene.fn"() ( {
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%2 = "serene.value"() {value = 0 : i64} : () -> i64
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return %2 : i64
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}) {args = {n = i64, v = i64, y = i64}, name = "main1", sym_visibility = "public"} : () -> i64
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}
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#+END_SRC
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*** Serene's MLIR (maybe we need a better name)
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Command line arguments to emir =mlir=
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#+BEGIN_SRC sh
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./builder run --build-dir ./build -emit mlir `pwd`/docs/examples/hello_world.srn
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#+END_SRC
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Output:
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#+BEGIN_SRC mlir
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module @user {
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func @main() -> i64 {
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%c3_i64 = constant 3 : i64
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return %c3_i64 : i64
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}
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func @main1(%arg0: i64, %arg1: i64, %arg2: i64) -> i64 {
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%c3_i64 = constant 3 : i64
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return %c3_i64 : i64
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}
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}
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#+END_SRC
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*** LIR
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Command line arguments to emir =lir=
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#+BEGIN_SRC sh
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./builder run --build-dir ./build -emit lir `pwd`/docs/examples/hello_world.srn
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#+END_SRC
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Output:
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#+BEGIN_SRC mlir
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module @user {
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llvm.func @main() -> i64 {
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%0 = llvm.mlir.constant(3 : i64) : i64
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llvm.return %0 : i64
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}
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llvm.func @main1(%arg0: i64, %arg1: i64, %arg2: i64) -> i64 {
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%0 = llvm.mlir.constant(3 : i64) : i64
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llvm.return %0 : i64
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}
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}
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#+END_SRC
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*** LLVMIR
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Command line arguments to emir =llvmir=
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#+BEGIN_SRC sh
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./builder run --build-dir ./build -emit ir `pwd`/docs/examples/hello_world.srn
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#+END_SRC
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Output:
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#+BEGIN_SRC llvm
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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declare i8* @malloc(i64 %0)
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declare void @free(i8* %0)
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define i64 @main() !dbg !3 {
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ret i64 3, !dbg !7
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}
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define i64 @main1(i64 %0, i64 %1, i64 %2) !dbg !9 {
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ret i64 3, !dbg !10
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}
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!2}
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!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "mlir", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
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!1 = !DIFile(filename: "LLVMDialectModule", directory: "/")
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!2 = !{i32 2, !"Debug Info Version", i32 3}
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!3 = distinct !DISubprogram(name: "main", linkageName: "main", scope: null, file: !4, type: !5, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !6)
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!4 = !DIFile(filename: "REPL", directory: "/home/lxsameer/src/serene/serene/build")
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!5 = !DISubroutineType(types: !6)
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!6 = !{}
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!7 = !DILocation(line: 0, column: 10, scope: !8)
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!8 = !DILexicalBlockFile(scope: !3, file: !4, discriminator: 0)
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!9 = distinct !DISubprogram(name: "main1", linkageName: "main1", scope: null, file: !4, line: 1, type: !5, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !6)
|
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!10 = !DILocation(line: 1, column: 11, scope: !11)
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!11 = !DILexicalBlockFile(scope: !9, file: !4, discriminator: 0)
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#+END_SRC
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|
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** Resources
|
||
- [[https://www.youtube.com/watch?v=Y4SvqTtOIDk][2020 LLVM Developers’ Meeting: M. Amini & R. Riddle “MLIR Tutorial”]]
|
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- [[https://www.youtube.com/watch?v=qzljG6DKgic][2019 EuroLLVM Developers’ Meeting: T. Shpeisman & C. Lattner “MLIR: Multi-Level Intermediate Repr..”]]
|
||
- https://mlir.llvm.org/docs
|
||
- https://mlir.llvm.org/docs/LangRef
|
||
- https://en.wikipedia.org/wiki/Basic_block
|
||
|
||
* DONE Episode 9 - IR (SLIR) generation
|
||
CLOSED: [2021-10-01 Fri 18:56]
|
||
** Updates:
|
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- Source manager
|
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- Diagnostic Engine
|
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- JIT
|
||
|
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There will be an episode dedicated to eache of these
|
||
** How does IR generation works
|
||
- Pass around MLIR context
|
||
- Create Builder objects that creates operations in specific
|
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locations
|
||
- ModuleOp
|
||
- Namespace
|
||
** How to define a new dialect
|
||
- Pure C++
|
||
- Tablegen
|
||
** SLIR
|
||
*** The SLIR goal
|
||
- An IR that follows the AST
|
||
- Rename?
|
||
*** Steps
|
||
- [X] Define the new dialect
|
||
- [X] Setup the tablegen
|
||
- [X] Define the operations
|
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- [X] Walk the AST and generate the operations
|
||
|
||
* DONE Episode 10 - Pass Infrastructure
|
||
CLOSED: [2021-10-15 Fri 14:17]
|
||
** The next Step
|
||
** Updates:
|
||
*** CMake changes
|
||
** What is a Pass
|
||
*** Passes are the unit of abstraction for optimization and transformation in LLVM/MLIR
|
||
*** Compilation is all about transforming the input data and produce an output
|
||
|
||
Source code -> IR X -> IR Y -> IR Z -> ... -> Target Code
|
||
|
||
*** Almost like a function composition
|
||
*** The big picture
|
||
*** Pass Managers (Pipelines) are made out of a collection of passes and can be nested
|
||
*** The most of the interesting parts of the compiler reside in Passes.
|
||
*** We will probably spend most of our time working with passes
|
||
|
||
** Pass Infrastructure
|
||
*** ODS or C++
|
||
*** Operation is the main abstract unit of transformation
|
||
*** OperationPass is the base class for all the passes.
|
||
*** We need to override =runOnOperation=
|
||
*** There's some rules you need to follow when defining your Pass
|
||
**** Must not maintain any global mutable state
|
||
**** Must not modify the state of another operation not nested within the current operation being operated on
|
||
**** ...
|
||
|
||
*** Passes are either OpSpecific or OpAgnostic
|
||
**** OpSpecific
|
||
#+BEGIN_SRC C++
|
||
struct MyFunctionPass : public PassWrapper<MyFunctionPass,
|
||
OperationPass<FuncOp>> {
|
||
void runOnOperation() override {
|
||
// Get the current FuncOp operation being operated on.
|
||
FuncOp f = getOperation();
|
||
|
||
// Walk the operations within the function.
|
||
f.walk([](Operation *inst) {
|
||
// ....
|
||
});
|
||
}
|
||
};
|
||
|
||
/// Register this pass so that it can be built via from a textual pass pipeline.
|
||
/// (Pass registration is discussed more below)
|
||
void registerMyPass() {
|
||
PassRegistration<MyFunctionPass>();
|
||
}
|
||
#+END_SRC
|
||
**** OpAgnostic
|
||
#+BEGIN_SRC C++
|
||
struct MyOperationPass : public PassWrapper<MyOperationPass, OperationPass<>> {
|
||
void runOnOperation() override {
|
||
// Get the current operation being operated on.
|
||
Operation *op = getOperation();
|
||
// ...
|
||
}
|
||
};
|
||
#+END_SRC
|
||
*** How transformation works?
|
||
*** Analyses and Passes
|
||
*** Pass management and nested pass managers
|
||
#+BEGIN_SRC C++
|
||
// Create a top-level `PassManager` class. If an operation type is not
|
||
// explicitly specific, the default is the builtin `module` operation.
|
||
PassManager pm(ctx);
|
||
|
||
// Note: We could also create the above `PassManager` this way.
|
||
PassManager pm(ctx, /*operationName=*/"builtin.module");
|
||
|
||
// Add a pass on the top-level module operation.
|
||
pm.addPass(std::make_unique<MyModulePass>());
|
||
|
||
// Nest a pass manager that operates on `spirv.module` operations nested
|
||
// directly under the top-level module.
|
||
OpPassManager &nestedModulePM = pm.nest<spirv::ModuleOp>();
|
||
nestedModulePM.addPass(std::make_unique<MySPIRVModulePass>());
|
||
|
||
// Nest a pass manager that operates on functions within the nested SPIRV
|
||
// module.
|
||
OpPassManager &nestedFunctionPM = nestedModulePM.nest<FuncOp>();
|
||
nestedFunctionPM.addPass(std::make_unique<MyFunctionPass>());
|
||
|
||
// Run the pass manager on the top-level module.
|
||
ModuleOp m = ...;
|
||
if (failed(pm.run(m))) {
|
||
// Handle the failure
|
||
}
|
||
#+END_SRC
|
||
|
||
* DONE Episode 11 - Lowering SLIR
|
||
CLOSED: [2021-11-01 Mon 15:14]
|
||
** Overview
|
||
- What is a Pass?
|
||
- Pass Manager
|
||
** Dialect lowering
|
||
*** Why?
|
||
*** Transforming a dialect to another dialect or LLVM IR
|
||
*** The goal is to lower SLIR to LLVM IR directly or indirectly.
|
||
** Dialect Conversions
|
||
This framework allows for transforming a set of illegal operations to a set of legal ones.
|
||
*** Target Conversion
|
||
*** Rewrite Patterns
|
||
*** Type Converter
|
||
** Full vs Partial Conversion
|
||
* DONE Episode 12 - Target code generation
|
||
CLOSED: [2021-11-04 Thu 00:57]
|
||
** Updates:
|
||
*** JIT work
|
||
*** Emacs dev mode
|
||
** So far....
|
||
** Next Step
|
||
*** Compile to object files
|
||
*** Link object files to create an executable
|
||
** End of wiring for static compilers
|
||
** What is an object file?
|
||
*** Symbols
|
||
- A pair of a name and a value
|
||
- Value of a *defined symbol* is an offset in the =Content=
|
||
- *undefined symbols*
|
||
*** Relocations
|
||
Are computation to perform on the =Content=. For example, "set
|
||
this location in the contents to the value of this symbol plus this addend".
|
||
|
||
Linker will apply all the *relocations* in an object file on link time and if
|
||
it can not resolve an undefined symbol most of the time it will raise an
|
||
error (depending on the relocation and the symbol).
|
||
|
||
*** Contents
|
||
- Are what memory should look like during the execution
|
||
- Have a size
|
||
- Have a type
|
||
- Have an array of bytes
|
||
- Has sections like: + .text: The target code generated by the compiler
|
||
+ .data: The values of initialized variables + .rdata: Static unnamed data like literal strings, protocol tables and ....
|
||
+ .bss: Uninitialized variables (the content can be omitted or striped and assume
|
||
to contain only zeros)
|
||
** Linking process
|
||
During the linking process, linker assigns an address to each *defined* symbol
|
||
and tries to =resolve= *undefined* symbols
|
||
*** Linker will
|
||
- reads the object files
|
||
- reads the contents + as raw data
|
||
+ figures out the length + reads the symbols and create a symbol table
|
||
+ link undefined symbols to their definitions (possibly from other obj fils or libs) + decide where all the content should go in the memory
|
||
+ sort them based on the *type* + concat them together
|
||
+ apply relocations
|
||
+ write the result to a file as an executable
|
||
** AOT vs JIT
|
||
** Let's look at some code
|
||
** Resources:
|
||
- [[https://lwn.net/Articles/276782/][20 part linker essay]]
|
||
* DONE Episode 13 - Source Managers
|
||
CLOSED: [2021-12-18 Sat 11:17]
|
||
** FAQ:
|
||
- What tools are you using?
|
||
|
||
** Updates:
|
||
- Still JIT
|
||
- We're going to start the JIT discussion from next EP
|
||
|
||
** Forgot to show case the code generation
|
||
I didn't show it in action
|
||
|
||
** What is a source manager
|
||
- It owns and manages are the source buffers
|
||
- All of our interactions with source files will happen though Source manager
|
||
- Including reading files
|
||
- Loading namespaces
|
||
- Including namespaces
|
||
- ...
|
||
|
||
- LLVM provides a =SourceMgr= class that we're not using it
|
||
* DONE Episode 14 - JIT Basics
|
||
CLOSED: [2022-01-05 Wed 17:37]
|
||
** Updates:
|
||
- Lost my data :_(
|
||
- Fixed some compatibility issues
|
||
- New video series on *How to build an editor with Emacs Lisp*
|
||
|
||
** What is Just In Time Compilation?
|
||
- Compiling at "runtime" (air quote)
|
||
Or it might be better to say, "on demand compilation"
|
||
- Usually in interpreters and Runtimes
|
||
|
||
#+NAME: ep-14-jit-1
|
||
#+BEGIN_SRC graphviz-dot :file /tmp/jit.svg :cmdline -Kdot -Tsvg
|
||
digraph {
|
||
graph [bgcolor=transparent]
|
||
node [color=gray80 shape="box"]
|
||
edge [color=gray80]
|
||
rankdir = "LR"
|
||
|
||
a[label="Some kind of input code"]
|
||
b[label="JIT"]
|
||
c[label="Some sort of target code"]
|
||
d[label="Execute the result"]
|
||
a -> b -> c -> d
|
||
}
|
||
#+END_SRC
|
||
|
||
#+RESULTS: ep-14-jit-1
|
||
[[file:/tmp/jit.svg]]
|
||
|
||
|
||
|
||
#+NAME: ep-14-jit-2
|
||
#+BEGIN_SRC graphviz-dot :file /tmp/jit-2.svg :cmdline -Kdot -Tsvg
|
||
|
||
digraph G {
|
||
graph [bgcolor=transparent]
|
||
node [color=gray80 shape="box"]
|
||
edge [color=gray80]
|
||
rankdir = "LR"
|
||
|
||
a[label="Source code"]
|
||
b[label="Parser"]
|
||
c[label="Semantic Analyzer"]
|
||
d[label="IR Generator"]
|
||
e[label="Pass Manager"]
|
||
f[label="Object Layer"]
|
||
g[label="Native Code"]
|
||
z[label="Preload Core libs"]
|
||
a -> b
|
||
b -> c {label="AST"}
|
||
c -> d
|
||
z -> f
|
||
subgraph cluster0 {
|
||
color=lightgrey;
|
||
d -> e -> f
|
||
label = "JIT Engine";
|
||
}
|
||
f -> g
|
||
g -> Store
|
||
g -> Execute
|
||
}
|
||
#+END_SRC
|
||
|
||
#+RESULTS: ep-14-jit-2
|
||
[[file:/tmp/jit-2.svg]]
|
||
|
||
|
||
- Trade off
|
||
Compilation speed vs Execution speed
|
||
*** JIT vs Typical interpreters
|
||
|
||
** Why to use JIT?
|
||
- Make the interpreter to run "faster" (air quote again)
|
||
- Speed up the compilation
|
||
Avoid generating the target code and generate some byte-code instead
|
||
and then use a JIT in runtime to execute the byte-code.
|
||
- Use runtime data to find optimization opportunities.
|
||
- Support more archs
|
||
- And many other reasons
|
||
** How we're going to use a JIT?
|
||
- We need a JIT engine to implement Lisp Macros
|
||
- Compile time vs Runtime
|
||
+ Abstraction
|
||
- A JIT engine to just compile Serene code
|
||
- Our compiler will be a fancy JIT engine
|
||
|
||
#+NAME: ep-14-jit-3
|
||
#+BEGIN_SRC graphviz-dot :file /tmp/jit-3.svg :cmdline -Kdot -Tsvg
|
||
digraph {
|
||
graph [bgcolor=transparent]
|
||
node [color=gray80 shape="box"]
|
||
edge [color=gray80]
|
||
rankdir = "LR"
|
||
|
||
a[label="Serene AST"]
|
||
b[label="For every node"]
|
||
c[label="is it a macro call?" shapp="diamond"]
|
||
d[label="Add it to JIT"]
|
||
e[label="Expand it (call it)"]
|
||
f[label="Generate target code"]
|
||
a -> b
|
||
|
||
|
||
subgraph cluster0 {
|
||
color=lightgrey;
|
||
b -> c
|
||
c -> d [label="NO"]
|
||
c -> e [label="YES"]
|
||
e -> b
|
||
d -> f
|
||
label = "JIT Engine";
|
||
}
|
||
|
||
f -> Store
|
||
f -> Execute
|
||
}
|
||
#+END_SRC
|
||
|
||
#+RESULTS: ep-14-jit-3
|
||
[[file:/tmp/jit-3.svg]]
|
||
|
||
|
||
** LLVM/MLIR and JIT
|
||
- 3 different approaches
|
||
- MLIR's JIT
|
||
- LLVM JITs + MCJIT (Deprecated)
|
||
+ LLJIT (Based on ORCv2) + LazyLLJIT (Based on LLJIT)
|
||
- Use LLVM's ORCv2 directly to create an engine
|
||
* DONE Episode 15 - LLVM ORC JIT
|
||
CLOSED: [2022-01-28 Fri 12:15]
|
||
** Uptades:
|
||
- Created a bare min JIT that:
|
||
- Eagrly compiles namespaces
|
||
- Reload namespacs
|
||
- I guess this the time to start the Serene's Spec
|
||
|
||
** What is ORCv2?
|
||
- On request compiler
|
||
- Replaces MCJIT
|
||
- ORCv2 docs and examples
|
||
- Kaleidoscope tutorial (not complete)
|
||
|
||
Before We can move to Serene's code we need to understand ORC first
|
||
|
||
** Terminology
|
||
*** Execution Session
|
||
A running JIT program. It contains the JITDylibs, error reporting mechanisms, and dispatches
|
||
the materializers.
|
||
|
||
*** JITAddress
|
||
It's just an address of a JITed code
|
||
|
||
*** JITDylib
|
||
Represents a JIT'd dynamic library.
|
||
|
||
This class aims to mimic the behavior of a shared object, but without requiring
|
||
the contained program representations to be compiled up-front. The JITDylib's
|
||
content is defined by adding MaterializationUnits, and contained MaterializationUnits
|
||
will typically rely on the JITDylib's links-against order to resolve external references.
|
||
|
||
JITDylibs cannot be moved or copied. Their address is stable, and useful as
|
||
a key in some JIT data structures.
|
||
|
||
*** MaterializationUnit
|
||
A =MaterializationUnit= represents a set of symbol definitions that can
|
||
be materialized as a group, or individually discarded (when
|
||
overriding definitions are encountered).
|
||
|
||
=MaterializationUnits= are used when providing lazy definitions of symbols to
|
||
JITDylibs. The JITDylib will call materialize when the address of a symbol
|
||
is requested via the lookup method. The =JITDylib= will call discard if a
|
||
stronger definition is added or already present.
|
||
|
||
MaterializationUnit stores in JITDylibs.
|
||
|
||
*** MaterializationResponsibility
|
||
Represents and tracks responsibility for materialization and mediates interactions between
|
||
=MaterializationUnits= and =JITDylibs=. It provides a way for Dylib to find out about the outcome
|
||
of the materialization.
|
||
|
||
*** Memory Manager
|
||
A class that manages how JIT engine should use memory, like allocations and deallocations.
|
||
=SectionMemoryManager= is a simple memory manager that is provided by ORC.
|
||
|
||
*** Layers
|
||
ORC based JIT engines are constructed from several layers. Each layer has a specific responsiblity
|
||
and passes the result of its operation to the next layer. E.g Compile Layer, Link layer and ....
|
||
|
||
*** Resource Tracker
|
||
The API to remove or transfer the ownership of JIT resources. Usually, a resource is a module.
|
||
|
||
*** ThreadSafeModule
|
||
A thread safe container for the LLVM module.
|
||
|
||
** ORC highlevel API
|
||
- ORC provides a Layer based design to that let us create our own JIT engine.
|
||
- It comes with two ready to use engines:
|
||
We will look at their implementaion later
|
||
+ LLJIT
|
||
+ LLLazyJIT
|
||
|
||
** Two major solutions to build a JIT
|
||
- Wrap LLJIT or LLLazyJIT
|
||
- Create your own JIT engine and the wrapper
|
||
|
||
** Resources
|
||
*** Docs
|
||
- https://www.llvm.org/docs/ORCv2.html
|
||
|
||
*** Examples
|
||
- https://github.com/llvm/llvm-project/tree/main/llvm/examples/HowToUseLLJIT
|
||
- https://github.com/llvm/llvm-project/tree/main/llvm/examples/OrcV2Examples/LLJITDumpObjects
|
||
- https://github.com/llvm/llvm-project/tree/main/llvm/examples/OrcV2Examples/LLJITWithInitializers
|
||
- https://github.com/llvm/llvm-project/tree/main/llvm/examples/OrcV2Examples/LLJITWithLazyReexports
|
||
|
||
*** Talks
|
||
- [[https://www.youtube.com/watch?v=i-inxFudrgI][ORCv2 -- LLVM JIT APIs Deep Dive]]
|
||
- [[https://www.youtube.com/watch?v=MOQG5vkh9J8][Updating ORC JIT for Concurrency]]
|
||
- [[https://www.youtube.com/watch?v=hILdR8XRvdQ][ORC -- LLVM's Next Generation of JIT API]]
|
||
* DONE Eposide 16 - ORC Layers
|
||
CLOSED: [2022-02-26 Sat 12:50]
|
||
** Updates:
|
||
*** Support for adding AST directly to the JIT
|
||
*** Minor change to SLIR (big changes are coming)
|
||
*** Started to unify the llvm::Errors with Serene errors
|
||
*** Tablegen backend for error classes
|
||
** The plan for today
|
||
- We had a brief look at LLJIT/LLLazyJIT
|
||
- Better understanding
|
||
To understand them better we need to understand other components first. Starting from *layers*.
|
||
- We'll have a look at how to define our own layers in the future episodes.
|
||
|
||
** What are Layers?
|
||
- Layers are the basic blocks of an engine
|
||
- They are composable (kinda)
|
||
- Each layer has it's own requirements and details
|
||
- Each layer holds a reference to it's downstream layer
|
||
|
||
#+NAME: ep-16-jit-1
|
||
#+BEGIN_SRC graphviz-dot :file /tmp/ep16-1.svg :cmdline -Kdot -Tsvg
|
||
digraph {
|
||
graph [bgcolor=transparent]
|
||
node [color=gray80 shape="box"]
|
||
edge [color=gray80]
|
||
rankdir = "LR"
|
||
|
||
a[label="Input Type A"]
|
||
b[label="Input Type B"]
|
||
c[label="Layer A"]
|
||
d[label="Layer B"]
|
||
e[label="Layer C"]
|
||
f[label="Layer D"]
|
||
g[label="Layer E"]
|
||
h[label="Target Code"]
|
||
a -> c
|
||
b -> d
|
||
|
||
subgraph cluster0 {
|
||
color=lightgrey;
|
||
c -> e
|
||
d -> e
|
||
e -> f
|
||
f -> g
|
||
|
||
label = "JIT Engine";
|
||
}
|
||
|
||
g -> h
|
||
}
|
||
#+END_SRC
|
||
|
||
#+RESULTS: ep-16-jit-1
|
||
[[file:/tmp/ep16-1.svg]]
|
||
|
||
** Kaleidoscope JIT
|
||
|
||
- Chapter 1
|
||
|
||
#+NAME: ep-16-jit-2
|
||
#+BEGIN_SRC graphviz-dot :file /tmp/ep16-2.svg :cmdline -Kdot -Tsvg
|
||
digraph {
|
||
graph [bgcolor=transparent]
|
||
node [color=gray80 shape="box"]
|
||
edge [color=gray80]
|
||
rankdir = "LR"
|
||
|
||
a[label="LLVM IR Module"]
|
||
b[label="Compiler Layer"]
|
||
c[label="Object Layer"]
|
||
d[label="Target Code"]
|
||
|
||
a -> b
|
||
|
||
subgraph cluster0 {
|
||
color=lightgrey;
|
||
b -> c
|
||
|
||
label = "Kaleidoscope JIT";
|
||
}
|
||
|
||
c -> d
|
||
}
|
||
#+END_SRC
|
||
|
||
#+RESULTS: ep-16-jit-2
|
||
[[file:/tmp/ep16-2.svg]]
|
||
|
||
- Chapter 2
|
||
#+NAME: ep-16-jit-3
|
||
#+BEGIN_SRC graphviz-dot :file /tmp/ep16-3.svg :cmdline -Kdot -Tsvg
|
||
digraph {
|
||
graph [bgcolor=transparent]
|
||
node [color=gray80 shape="box"]
|
||
edge [color=gray80]
|
||
rankdir = "LR"
|
||
|
||
a[label="LLVM IR Module"]
|
||
b[label="Compiler Layer"]
|
||
c[label="Object Layer"]
|
||
e[label="Target Code"]
|
||
d[label="Optimize layer"]
|
||
a -> d
|
||
|
||
subgraph cluster0 {
|
||
color=lightgrey;
|
||
d -> b
|
||
b -> c
|
||
|
||
label = "Kaleidoscope JIT";
|
||
}
|
||
|
||
c -> e
|
||
}
|
||
#+END_SRC
|
||
|
||
#+RESULTS: ep-16-jit-3
|
||
[[file:/tmp/ep16-3.svg]]
|
||
|
||
* DONE Episode 17 - Custom ORC Layers
|
||
CLOSED: [2022-03-28 Mon 14:00]
|
||
** Updates:
|
||
- Finished the basic compiler wiring
|
||
- Restructured the source tree
|
||
- Tweaked the build system mostly for install targets
|
||
- Refactoring, cleaning up the code and writing tests
|
||
** Quick overview an ORC based JIT engine
|
||
- JIT engines are made out of layers
|
||
- Engines have a hierarchy of layers
|
||
- Layers don't know about each other
|
||
- Layers wrap the program representation in a =MaterializationUnit=, which is
|
||
then stored in the =JITDylib=.
|
||
- =MaterializationUnits= are responsible for describing the definitions they provide,
|
||
and for unwrapping the program representation and passing it back to the layer when
|
||
compilation is required.
|
||
- When a =MaterializationUnit= hands a program representation back to the layer it comes
|
||
with an associated =MaterializationResponsibility= object. This object tracks the
|
||
definitions that must be materialized and provides a way to notify the =JITDylib= once
|
||
they are either successfully materialized or a failure occurs.
|
||
|
||
** In order to build a custom layer we need:
|
||
*** A custom materialization unit
|
||
Let's have a look at the =MaterializationUnit= class.
|
||
|
||
*** And the layer class itself
|
||
The layer classes are not special but conventionally the come with few functions
|
||
like: =add=, =emit= and =getInterface=.
|
||
|
||
* DONE Episode 18 - JIT Engine Part 1
|
||
CLOSED: [2022-03-29 Tue 19:56]
|
||
** =Halley= JIT Engine
|
||
- It's not the final implementation
|
||
- Wraps LLJIT and LLLazyJIT
|
||
- Uses object cache layer
|
||
- Supports ASTs and Namespaces
|
||
|
||
* DONE Episode 19 - JIT Engine Part 2
|
||
CLOSED: [2022-05-04 Wed 21:30]
|
||
** How Serene is different from other programming langs?
|
||
- Serene is just a JIT engine
|
||
- Compiletime vs Runtime
|
||
+ The borderline is not clear in case of Serene
|
||
|
||
The Big picture
|
||
#+NAME: ep-19-jit-1
|
||
#+BEGIN_SRC graphviz-dot :file /tmp/ep19-1.svg :cmdline -Kdot -Tsvg
|
||
digraph {
|
||
fontcolor="gray80"
|
||
|
||
graph [bgcolor=transparent]
|
||
node [color=gray80 shape="box", fontcolor="gray80"]
|
||
edge [color=gray80, fontcolor="gray80"]
|
||
|
||
|
||
input_ns[label="Input Namespace"]
|
||
|
||
ast[label="AST"]
|
||
vast[label="Valid AST"]
|
||
ir[label="LLVM IR"]
|
||
|
||
subgraph cluster_2 {
|
||
label="REPL"
|
||
color="gray80"
|
||
|
||
graph [bgcolor=transparent, fontcolor="gray80"]
|
||
node [color=gray80 shape="box", fontcolor="gray80"]
|
||
|
||
input_form[label="Input Form"]
|
||
result[label="Evaluation result"]
|
||
result -> input_form[label="Loop"]
|
||
}
|
||
|
||
subgraph cluster_0 {
|
||
label="JIT"
|
||
color="gray80"
|
||
|
||
graph [bgcolor=transparent, fontcolor="gray80"]
|
||
node [color=gray80 shape="box", fontcolor="gray80"]
|
||
|
||
|
||
execute[label="Execute native code"]
|
||
binary[label="Binary File"]
|
||
|
||
subgraph cluster_1 {
|
||
label="AddAst/Ns"
|
||
color="gray80"
|
||
|
||
graph [bgcolor=transparent, fontcolor="gray80"]
|
||
node [color=gray80 shape="box", fontcolor="gray80"]
|
||
|
||
vast -> ir [label="Compile (No optimization)"]
|
||
|
||
subgraph cluster_4 {
|
||
label="Macro Expansion"
|
||
color="gray80"
|
||
|
||
graph [bgcolor=transparent, fontcolor="gray80"]
|
||
node [color=gray80 shape="box", fontcolor="gray80"]
|
||
|
||
vast -> macros [label=" Find the macros"]
|
||
macros -> JITDylib [label=" look up the required\n Symbols in compiled code"]
|
||
JITDylib -> symbols [label=" lookup"]
|
||
}
|
||
|
||
wrapped_code[lable="Wrapped IR"]
|
||
ir -> wrapped_code[label= " Wrap top level Forms in \nfunctions/calls"]
|
||
wrapped_code -> native [label=" Compile (No optimization)"]
|
||
}
|
||
|
||
symbols -> execute [label="Execute the functions mapped to the symbols"]
|
||
execute -> vast
|
||
execute -> result [label=" Print"]
|
||
execute -> binary [label=" Dump"]
|
||
|
||
native -> execute [label="invoke"]
|
||
native -> JITDylib [label="Add"]
|
||
JITDylib -> Context [label="Store as part the namespace"]
|
||
}
|
||
|
||
subgraph cluster_3 {
|
||
label="CLI interface"
|
||
color="gray80"
|
||
|
||
graph [bgcolor=transparent, fontcolor="gray80"]
|
||
node [color=gray80 shape="box", fontcolor="gray80"]
|
||
|
||
input_ns -> file [label=" resolve to file"]
|
||
}
|
||
|
||
input_form -> ast [label=" read"]
|
||
file -> ast [label=" read"]
|
||
ast -> vast [label=" Semantic Analysis"]
|
||
}
|
||
#+END_SRC
|
||
|
||
#+RESULTS: ep-19-jit-1
|
||
[[file:/tmp/ep19-1.png]]
|
||
** Let's look at some code
|
||
* Episode 20 - Future Roadmap
|
||
** So Far
|
||
- We created a bare bone and minimal compiler
|
||
+ That is capable of just in time and ahead of time compilation
|
||
- We had an over of MLIR and pass management
|
||
- We didn't spend time on fundamentals
|
||
** Design change
|
||
- The current implementation is suitable for a static compiler
|
||
- We want to move toward a more dynamic compiler
|
||
** What's next?
|
||
- Part 2
|
||
- We're going to focus on some of the compiler fundamentals
|
||
- We will create simple utilities to help us in our journey
|
||
- Hopefully we will talk about type systems
|
||
- We're going to sharpen our skills on LLVM/MLIR
|
||
- I'm going to work on the new design
|