IRx

IRx is a Python library that lowers ARXLang ASTx nodes to LLVM IR using llvmlite. It provides a visitor-based codegen pipeline and a small builder API that can translate ASTs to LLVM IR text or produce runnable executables via clang.

Status: early but functional. Arithmetic, variables, functions, returns, basic control flow, and a few system-level expressions (e.g. PrintExpr) are supported.

Features

• ASTx → LLVM IR via multiple-dispatch visitors (plum).

• Back end: IR construction and object emission with llvmlite.

• Native build: links with clang to produce an executable.

• Supported nodes (subset; exact ASTx class names):

  • Literals: LiteralInt16, LiteralInt32, LiteralString
  • Variables: Variable, VariableDeclaration, InlineVariableDeclaration
  • Ops: UnaryOp (++, --), BinaryOp (+ - * / < >) with simple type promotion
  • Flow: IfStmt, ForCountLoopStmt, ForRangeLoopStmt
  • Functions: FunctionPrototype, Function, FunctionReturn, FunctionCall
  • System: system.PrintExpr (string printing)

• Built-ins: putchar, putchard (emitted as IR); puts declaration when needed.

Quick Start

Requirements

• Python 3.9 – 3.13.

• A recent LLVM/Clang toolchain available on PATH.

• A working C standard library (e.g., system libc) for linking calls like puts.

• Python deps: llvmlite, pytest, etc. (see pyproject.toml / requirements.txt).

  • Note: llvmlite has specific Python/LLVM compatibility windows; see its docs.

Install (dev)

git clone https://github.com/arxlang/irx.git
cd irx
conda env create --file conda/dev.yaml
conda activate irx
poetry install

You can also install it from PyPI: pip install pyirx.

More details: https://irx.arxlang.org/installation/

Minimal Examples

1) Translate to LLVM IR (no linking)

import astx
from irx.builders.llvmliteir import LLVMLiteIR

builder = LLVMLiteIR()
module = builder.module()

# int main() { return 0; }
proto = astx.FunctionPrototype("main", astx.Arguments(), astx.Int32())
body = astx.Block()
body.append(astx.FunctionReturn(astx.LiteralInt32(0)))
module.block.append(astx.Function(prototype=proto, body=body))

ir_text = builder.translate(module)
print(ir_text)  # LLVM IR text (str)

translate returns a str with LLVM IR. It does not produce an object file or binary; use it for inspection, tests, or feeding another tool.

2) Build and run a tiny program that prints and returns 0

import astx
from irx.builders.llvmliteir import LLVMLiteIR
from irx.system import PrintExpr

builder = LLVMLiteIR()
module = builder.module()

# int main() { print("Hello, IRx!"); return 0; }
main_proto = astx.FunctionPrototype("main", astx.Arguments(), astx.Int32())
body = astx.Block()
body.append(PrintExpr(astx.LiteralString("Hello, IRx!")))
body.append(astx.FunctionReturn(astx.LiteralInt32(0)))
module.block.append(astx.Function(prototype=main_proto, body=body))

builder.build(module, "hello")  # emits object + links with clang
builder.run()                   # executes ./hello (or hello.exe on Windows)

How It Works

Builders & Visitors

• LLVMLiteIR (public API)

  • translate(ast) -> str — generate LLVM IR text.
  • build(ast, output_path) — emit object via llvmlite and link with clang.
  • run() — execute the produced binary.

• LLVMLiteIRVisitor (codegen)

  • Uses @dispatch to visit each ASTx node type.
  • Maintains a value stack (result_stack) and symbol table (named_values).
  • Emits LLVM IR with llvmlite.ir.IRBuilder.

System Printing

PrintExpr is an astx.Expr holding a LiteralString. Its lowering:

1. Create a global constant for the string (with \0).
2. GEP to an i8* pointer.
3. Declare (or reuse) i32 @puts(i8*).
4. Call puts.

Testing

pytest -vv

Example style (simplified):

def test_binary_op_basic():
    builder = LLVMLiteIR()
    module = builder.module()

    decl_a = astx.VariableDeclaration("a", astx.Int32(), astx.LiteralInt32(1))
    decl_b = astx.VariableDeclaration("b", astx.Int32(), astx.LiteralInt32(2))

    a, b = astx.Variable("a"), astx.Variable("b")
    expr = astx.LiteralInt32(1) + b - a * b / a

    proto = astx.FunctionPrototype("main", astx.Arguments(), astx.Int32())
    block = astx.Block()
    block.append(decl_a); block.append(decl_b)
    block.append(astx.FunctionReturn(expr))
    module.block.append(astx.Function(proto, block))

    ir_text = builder.translate(module)
    assert "add" in ir_text

Troubleshooting

macOS: ld: library 'System' not found

• Ensure Xcode Command Line Tools are installed: xcode-select --install.

• Verify clang --version works.

• If needed:

  export SDKROOT="$(xcrun --sdk macosx --show-sdk-path)"

• CI note: macOS jobs currently run on Python 3.12 only.

Non-zero exit when function returns void

• Define main to return Int32 and emit return 0. Falling off the end or returning void can yield an arbitrary exit code.

plum.resolver.NotFoundLookupError

• A visitor is missing @dispatch or is typed against a different class than the one instantiated. Ensure signatures match the exact runtime class (e.g., visit(self, node: PrintExpr)).

Linker or clang not found

• Install a recent LLVM/Clang. On Linux, use distro packages.
• On macOS, install Xcode CLT.
• On Windows, ensure LLVM’s bin directory is on PATH.

Platform Notes

• Linux & macOS: supported and used in CI.
• Windows: expected to work with a proper LLVM/Clang setup; consider it experimental. builder.run() will execute hello.exe.

Roadmap

• More ASTx coverage (booleans, arrays, structs, varargs/options).
• Richer stdlib bindings (I/O, math).
• Optimization toggles/passes.
• Alternative backends and/or JIT runner.
• Better diagnostics and source locations in IR.
• Integration with Apache Arrow.

Contributing

Please see the contributing guide. Add tests for new features and keep visitors isolated (avoid special-casing derived nodes inside generic visitors).

Acknowledgments

• LLVM and llvmlite for the IR infrastructure.
• ASTx / ARXLang for the front-end AST.
• Contributors and users experimenting with IRx.

License

License: BSD-3-Clause. See LICENSE.