refactor(users/glittershark): Rename to grfn r/2485

Rename my //users directory and all places that refer to glittershark to
grfn, including nix references and documentation.

This may require some extra attention inside of gerrit's database after
it lands to allow me to actually push things.

Change-Id: I4728b7ec2c60024392c1c1fa6e0d4a59b3e266fa
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2933
Tested-by: BuildkiteCI
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: glittershark <grfn@gws.fyi>

2 files changed, 461 insertions, 0 deletions

diff --git a/users/grfn/achilles/src/codegen/llvm.rs b/users/grfn/achilles/src/codegen/llvm.rs
new file mode 100644
index 0000000000..17dec58b5f
--- /dev/null
+++ b/users/grfn/achilles/src/codegen/llvm.rs
@@ -0,0 +1,436 @@
+use std::convert::{TryFrom, TryInto};
+use std::path::Path;
+use std::result;
+
+use inkwell::basic_block::BasicBlock;
+use inkwell::builder::Builder;
+pub use inkwell::context::Context;
+use inkwell::module::Module;
+use inkwell::support::LLVMString;
+use inkwell::types::{BasicType, BasicTypeEnum, FunctionType, IntType};
+use inkwell::values::{AnyValueEnum, BasicValueEnum, FunctionValue};
+use inkwell::{AddressSpace, IntPredicate};
+use thiserror::Error;
+
+use crate::ast::hir::{Binding, Decl, Expr};
+use crate::ast::{BinaryOperator, Ident, Literal, Type, UnaryOperator};
+use crate::common::env::Env;
+
+#[derive(Debug, PartialEq, Eq, Error)]
+pub enum Error {
+    #[error("Undefined variable {0}")]
+    UndefinedVariable(Ident<'static>),
+
+    #[error("LLVM Error: {0}")]
+    LLVMError(String),
+}
+
+impl From<LLVMString> for Error {
+    fn from(s: LLVMString) -> Self {
+        Self::LLVMError(s.to_string())
+    }
+}
+
+pub type Result<T> = result::Result<T, Error>;
+
+pub struct Codegen<'ctx, 'ast> {
+    context: &'ctx Context,
+    pub module: Module<'ctx>,
+    builder: Builder<'ctx>,
+    env: Env<&'ast Ident<'ast>, AnyValueEnum<'ctx>>,
+    function_stack: Vec<FunctionValue<'ctx>>,
+    identifier_counter: u32,
+}
+
+impl<'ctx, 'ast> Codegen<'ctx, 'ast> {
+    pub fn new(context: &'ctx Context, module_name: &str) -> Self {
+        let module = context.create_module(module_name);
+        let builder = context.create_builder();
+        Self {
+            context,
+            module,
+            builder,
+            env: Default::default(),
+            function_stack: Default::default(),
+            identifier_counter: 0,
+        }
+    }
+
+    pub fn new_function<'a>(
+        &'a mut self,
+        name: &str,
+        ty: FunctionType<'ctx>,
+    ) -> &'a FunctionValue<'ctx> {
+        self.function_stack
+            .push(self.module.add_function(name, ty, None));
+        let basic_block = self.append_basic_block("entry");
+        self.builder.position_at_end(basic_block);
+        self.function_stack.last().unwrap()
+    }
+
+    pub fn finish_function(&mut self, res: Option<&BasicValueEnum<'ctx>>) -> FunctionValue<'ctx> {
+        self.builder.build_return(match res {
+            // lol
+            Some(val) => Some(val),
+            None => None,
+        });
+        self.function_stack.pop().unwrap()
+    }
+
+    pub fn append_basic_block(&self, name: &str) -> BasicBlock<'ctx> {
+        self.context
+            .append_basic_block(*self.function_stack.last().unwrap(), name)
+    }
+
+    pub fn codegen_expr(
+        &mut self,
+        expr: &'ast Expr<'ast, Type>,
+    ) -> Result<Option<AnyValueEnum<'ctx>>> {
+        match expr {
+            Expr::Ident(id, _) => self
+                .env
+                .resolve(id)
+                .cloned()
+                .ok_or_else(|| Error::UndefinedVariable(id.to_owned()))
+                .map(Some),
+            Expr::Literal(lit, ty) => {
+                let ty = self.codegen_int_type(ty);
+                match lit {
+                    Literal::Int(i) => Ok(Some(AnyValueEnum::IntValue(ty.const_int(*i, false)))),
+                    Literal::Bool(b) => Ok(Some(AnyValueEnum::IntValue(
+                        ty.const_int(if *b { 1 } else { 0 }, false),
+                    ))),
+                    Literal::String(s) => Ok(Some(
+                        self.builder
+                            .build_global_string_ptr(s, "s")
+                            .as_pointer_value()
+                            .into(),
+                    )),
+                    Literal::Unit => Ok(None),
+                }
+            }
+            Expr::UnaryOp { op, rhs, .. } => {
+                let rhs = self.codegen_expr(rhs)?.unwrap();
+                match op {
+                    UnaryOperator::Not => unimplemented!(),
+                    UnaryOperator::Neg => Ok(Some(AnyValueEnum::IntValue(
+                        self.builder.build_int_neg(rhs.into_int_value(), "neg"),
+                    ))),
+                }
+            }
+            Expr::BinaryOp { lhs, op, rhs, .. } => {
+                let lhs = self.codegen_expr(lhs)?.unwrap();
+                let rhs = self.codegen_expr(rhs)?.unwrap();
+                match op {
+                    BinaryOperator::Add => {
+                        Ok(Some(AnyValueEnum::IntValue(self.builder.build_int_add(
+                            lhs.into_int_value(),
+                            rhs.into_int_value(),
+                            "add",
+                        ))))
+                    }
+                    BinaryOperator::Sub => {
+                        Ok(Some(AnyValueEnum::IntValue(self.builder.build_int_sub(
+                            lhs.into_int_value(),
+                            rhs.into_int_value(),
+                            "add",
+                        ))))
+                    }
+                    BinaryOperator::Mul => {
+                        Ok(Some(AnyValueEnum::IntValue(self.builder.build_int_sub(
+                            lhs.into_int_value(),
+                            rhs.into_int_value(),
+                            "add",
+                        ))))
+                    }
+                    BinaryOperator::Div => Ok(Some(AnyValueEnum::IntValue(
+                        self.builder.build_int_signed_div(
+                            lhs.into_int_value(),
+                            rhs.into_int_value(),
+                            "add",
+                        ),
+                    ))),
+                    BinaryOperator::Pow => unimplemented!(),
+                    BinaryOperator::Equ => Ok(Some(AnyValueEnum::IntValue(
+                        self.builder.build_int_compare(
+                            IntPredicate::EQ,
+                            lhs.into_int_value(),
+                            rhs.into_int_value(),
+                            "eq",
+                        ),
+                    ))),
+                    BinaryOperator::Neq => todo!(),
+                }
+            }
+            Expr::Let { bindings, body, .. } => {
+                self.env.push();
+                for Binding { ident, body, .. } in bindings {
+                    if let Some(val) = self.codegen_expr(body)? {
+                        self.env.set(ident, val);
+                    }
+                }
+                let res = self.codegen_expr(body);
+                self.env.pop();
+                res
+            }
+            Expr::If {
+                condition,
+                then,
+                else_,
+                type_,
+            } => {
+                let then_block = self.append_basic_block("then");
+                let else_block = self.append_basic_block("else");
+                let join_block = self.append_basic_block("join");
+                let condition = self.codegen_expr(condition)?.unwrap();
+                self.builder.build_conditional_branch(
+                    condition.into_int_value(),
+                    then_block,
+                    else_block,
+                );
+                self.builder.position_at_end(then_block);
+                let then_res = self.codegen_expr(then)?;
+                self.builder.build_unconditional_branch(join_block);
+
+                self.builder.position_at_end(else_block);
+                let else_res = self.codegen_expr(else_)?;
+                self.builder.build_unconditional_branch(join_block);
+
+                self.builder.position_at_end(join_block);
+                if let Some(phi_type) = self.codegen_type(type_) {
+                    let phi = self.builder.build_phi(phi_type, "join");
+                    phi.add_incoming(&[
+                        (
+                            &BasicValueEnum::try_from(then_res.unwrap()).unwrap(),
+                            then_block,
+                        ),
+                        (
+                            &BasicValueEnum::try_from(else_res.unwrap()).unwrap(),
+                            else_block,
+                        ),
+                    ]);
+                    Ok(Some(phi.as_basic_value().into()))
+                } else {
+                    Ok(None)
+                }
+            }
+            Expr::Call { fun, args, .. } => {
+                if let Expr::Ident(id, _) = &**fun {
+                    let function = self
+                        .module
+                        .get_function(id.into())
+                        .or_else(|| self.env.resolve(id)?.clone().try_into().ok())
+                        .ok_or_else(|| Error::UndefinedVariable(id.to_owned()))?;
+                    let args = args
+                        .iter()
+                        .map(|arg| Ok(self.codegen_expr(arg)?.unwrap().try_into().unwrap()))
+                        .collect::<Result<Vec<_>>>()?;
+                    Ok(self
+                        .builder
+                        .build_call(function, &args, "call")
+                        .try_as_basic_value()
+                        .left()
+                        .map(|val| val.into()))
+                } else {
+                    todo!()
+                }
+            }
+            Expr::Fun { args, body, .. } => {
+                let fname = self.fresh_ident("f");
+                let cur_block = self.builder.get_insert_block().unwrap();
+                let env = self.env.save(); // TODO: closures
+                let function = self.codegen_function(&fname, args, body)?;
+                self.builder.position_at_end(cur_block);
+                self.env.restore(env);
+                Ok(Some(function.into()))
+            }
+        }
+    }
+
+    pub fn codegen_function(
+        &mut self,
+        name: &str,
+        args: &'ast [(Ident<'ast>, Type)],
+        body: &'ast Expr<'ast, Type>,
+    ) -> Result<FunctionValue<'ctx>> {
+        let arg_types = args
+            .iter()
+            .filter_map(|(_, at)| self.codegen_type(at))
+            .collect::<Vec<_>>();
+
+        self.new_function(
+            name,
+            match self.codegen_type(body.type_()) {
+                Some(ret_ty) => ret_ty.fn_type(&arg_types, false),
+                None => self.context.void_type().fn_type(&arg_types, false),
+            },
+        );
+        self.env.push();
+        for (i, (arg, _)) in args.iter().enumerate() {
+            self.env.set(
+                arg,
+                self.cur_function().get_nth_param(i as u32).unwrap().into(),
+            );
+        }
+        let res = self.codegen_expr(body)?;
+        self.env.pop();
+        Ok(self.finish_function(res.map(|av| av.try_into().unwrap()).as_ref()))
+    }
+
+    pub fn codegen_extern(
+        &mut self,
+        name: &str,
+        args: &'ast [Type],
+        ret: &'ast Type,
+    ) -> Result<()> {
+        let arg_types = args
+            .iter()
+            .map(|t| self.codegen_type(t).unwrap())
+            .collect::<Vec<_>>();
+        self.module.add_function(
+            name,
+            match self.codegen_type(ret) {
+                Some(ret_ty) => ret_ty.fn_type(&arg_types, false),
+                None => self.context.void_type().fn_type(&arg_types, false),
+            },
+            None,
+        );
+        Ok(())
+    }
+
+    pub fn codegen_decl(&mut self, decl: &'ast Decl<'ast, Type>) -> Result<()> {
+        match decl {
+            Decl::Fun {
+                name, args, body, ..
+            } => {
+                self.codegen_function(name.into(), args, body)?;
+                Ok(())
+            }
+            Decl::Extern {
+                name,
+                arg_types,
+                ret_type,
+            } => self.codegen_extern(name.into(), arg_types, ret_type),
+        }
+    }
+
+    pub fn codegen_main(&mut self, expr: &'ast Expr<'ast, Type>) -> Result<()> {
+        self.new_function("main", self.context.i64_type().fn_type(&[], false));
+        let res = self.codegen_expr(expr)?;
+        if *expr.type_() != Type::Int {
+            self.builder
+                .build_return(Some(&self.context.i64_type().const_int(0, false)));
+        } else {
+            self.finish_function(res.map(|r| r.try_into().unwrap()).as_ref());
+        }
+        Ok(())
+    }
+
+    fn codegen_type(&self, type_: &'ast Type) -> Option<BasicTypeEnum<'ctx>> {
+        // TODO
+        match type_ {
+            Type::Int => Some(self.context.i64_type().into()),
+            Type::Float => Some(self.context.f64_type().into()),
+            Type::Bool => Some(self.context.bool_type().into()),
+            Type::CString => Some(
+                self.context
+                    .i8_type()
+                    .ptr_type(AddressSpace::Generic)
+                    .into(),
+            ),
+            Type::Function(_) => todo!(),
+            Type::Var(_) => unreachable!(),
+            Type::Unit => None,
+        }
+    }
+
+    fn codegen_int_type(&self, type_: &'ast Type) -> IntType<'ctx> {
+        // TODO
+        self.context.i64_type()
+    }
+
+    pub fn print_to_file<P>(&self, path: P) -> Result<()>
+    where
+        P: AsRef<Path>,
+    {
+        Ok(self.module.print_to_file(path)?)
+    }
+
+    pub fn binary_to_file<P>(&self, path: P) -> Result<()>
+    where
+        P: AsRef<Path>,
+    {
+        if self.module.write_bitcode_to_path(path.as_ref()) {
+            Ok(())
+        } else {
+            Err(Error::LLVMError(
+                "Error writing bitcode to output path".to_owned(),
+            ))
+        }
+    }
+
+    fn fresh_ident(&mut self, prefix: &str) -> String {
+        self.identifier_counter += 1;
+        format!("{}{}", prefix, self.identifier_counter)
+    }
+
+    fn cur_function(&self) -> &FunctionValue<'ctx> {
+        self.function_stack.last().unwrap()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use inkwell::execution_engine::JitFunction;
+    use inkwell::OptimizationLevel;
+
+    use super::*;
+
+    fn jit_eval<T>(expr: &str) -> anyhow::Result<T> {
+        let expr = crate::parser::expr(expr).unwrap().1;
+
+        let expr = crate::tc::typecheck_expr(expr).unwrap();
+
+        let context = Context::create();
+        let mut codegen = Codegen::new(&context, "test");
+        let execution_engine = codegen
+            .module
+            .create_jit_execution_engine(OptimizationLevel::None)
+            .unwrap();
+
+        codegen.codegen_function("test", &[], &expr)?;
+
+        unsafe {
+            let fun: JitFunction<unsafe extern "C" fn() -> T> =
+                execution_engine.get_function("test")?;
+            Ok(fun.call())
+        }
+    }
+
+    #[test]
+    fn add_literals() {
+        assert_eq!(jit_eval::<i64>("1 + 2").unwrap(), 3);
+    }
+
+    #[test]
+    fn variable_shadowing() {
+        assert_eq!(
+            jit_eval::<i64>("let x = 1 in (let x = 2 in x) + x").unwrap(),
+            3
+        );
+    }
+
+    #[test]
+    fn eq() {
+        assert_eq!(
+            jit_eval::<i64>("let x = 1 in if x == 1 then 2 else 4").unwrap(),
+            2
+        );
+    }
+
+    #[test]
+    fn function_call() {
+        let res = jit_eval::<i64>("let id = fn x = x in id 1").unwrap();
+        assert_eq!(res, 1);
+    }
+}
diff --git a/users/grfn/achilles/src/codegen/mod.rs b/users/grfn/achilles/src/codegen/mod.rs
new file mode 100644
index 0000000000..8ef057dba0
--- /dev/null
+++ b/users/grfn/achilles/src/codegen/mod.rs
@@ -0,0 +1,25 @@
+pub mod llvm;
+
+use inkwell::execution_engine::JitFunction;
+use inkwell::OptimizationLevel;
+pub use llvm::*;
+
+use crate::ast::hir::Expr;
+use crate::ast::Type;
+use crate::common::Result;
+
+pub fn jit_eval<T>(expr: &Expr<Type>) -> Result<T> {
+    let context = Context::create();
+    let mut codegen = Codegen::new(&context, "eval");
+    let execution_engine = codegen
+        .module
+        .create_jit_execution_engine(OptimizationLevel::None)
+        .map_err(Error::from)?;
+    codegen.codegen_function("test", &[], &expr)?;
+
+    unsafe {
+        let fun: JitFunction<unsafe extern "C" fn() -> T> =
+            execution_engine.get_function("eval").unwrap();
+        Ok(fun.call())
+    }
+}