nac3/nac3core/src/codegen/stmt.rs

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use std::convert::TryInto;
use crate::{top_level::CodeGenContext, typecheck::typedef::Type};
use inkwell::{
types::BasicTypeEnum,
values::{BasicValueEnum, PointerValue},
};
use rustpython_parser::ast::{Expr, ExprKind, Stmt, StmtKind};
impl<'ctx> CodeGenContext<'ctx> {
fn gen_var(&mut self, ty: Type) -> PointerValue<'ctx> {
let ty = self.get_llvm_type(ty);
let ty = if let BasicTypeEnum::PointerType(ty) = ty {
ty.get_element_type().try_into().unwrap()
} else {
ty
};
self.builder.build_alloca(ty, "tmp")
}
fn parse_pattern(&mut self, pattern: &Expr<Option<Type>>) -> PointerValue<'ctx> {
// very similar to gen_expr, but we don't do an extra load at the end
// and we flatten nested tuples
match &pattern.node {
ExprKind::Name { id, .. } => {
self.var_assignment.get(id).cloned().unwrap_or_else(|| {
let ptr = self.gen_var(pattern.custom.unwrap());
self.var_assignment.insert(id.clone(), ptr);
ptr
})
}
ExprKind::Attribute { value, attr, .. } => {
let index = self.get_attr_index(value.custom.unwrap(), attr);
let val = self.gen_expr(value);
let ptr = if let BasicValueEnum::PointerValue(v) = val {
v
} else {
unreachable!();
};
unsafe {
ptr.const_in_bounds_gep(&[
self.ctx.i32_type().const_zero(),
self.ctx.i32_type().const_int(index as u64, false),
])
}
}
ExprKind::Subscript { .. } => unimplemented!(),
_ => unreachable!(),
}
}
fn gen_assignment(&mut self, target: &Expr<Option<Type>>, value: BasicValueEnum<'ctx>) {
if let ExprKind::Tuple { elts, .. } = &target.node {
if let BasicValueEnum::PointerValue(ptr) = value {
for (i, elt) in elts.iter().enumerate() {
unsafe {
let t = ptr.const_in_bounds_gep(&[
self.ctx.i32_type().const_zero(),
self.ctx.i32_type().const_int(i as u64, false),
]);
let v = self.builder.build_load(t, "tmpload");
self.gen_assignment(elt, v);
}
}
} else {
unreachable!()
}
} else {
let ptr = self.parse_pattern(target);
self.builder.build_store(ptr, value);
}
}
pub fn gen_stmt(&mut self, stmt: &Stmt<Option<Type>>) {
match &stmt.node {
StmtKind::Expr { value } => {
self.gen_expr(&value);
}
StmtKind::Assign { targets, value, .. } => {
let value = self.gen_expr(&value);
for target in targets.iter() {
self.gen_assignment(target, value);
}
}
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StmtKind::Continue => {
self.builder.build_unconditional_branch(self.loop_bb.unwrap().0);
}
StmtKind::Break => {
self.builder.build_unconditional_branch(self.loop_bb.unwrap().1);
}
StmtKind::While { test, body, orelse } => {
let current = self.builder.get_insert_block().unwrap().get_parent().unwrap();
let test_bb = self.ctx.append_basic_block(current, "test");
let body_bb = self.ctx.append_basic_block(current, "body");
let cont_bb = self.ctx.append_basic_block(current, "cont");
// if there is no orelse, we just go to cont_bb
let orelse_bb = if orelse.is_empty() {
cont_bb
} else {
self.ctx.append_basic_block(current, "orelse")
};
// store loop bb information and restore it later
let loop_bb = self.loop_bb.replace((test_bb, cont_bb));
self.builder.build_unconditional_branch(test_bb);
self.builder.position_at_end(test_bb);
let test = self.gen_expr(test);
if let BasicValueEnum::IntValue(test) = test {
self.builder.build_conditional_branch(test, body_bb, orelse_bb);
} else {
unreachable!()
};
self.builder.position_at_end(body_bb);
for stmt in body.iter() {
self.gen_stmt(stmt);
}
self.builder.build_unconditional_branch(test_bb);
if !orelse.is_empty() {
self.builder.position_at_end(orelse_bb);
for stmt in orelse.iter() {
self.gen_stmt(stmt);
}
self.builder.build_unconditional_branch(cont_bb);
}
self.builder.position_at_end(cont_bb);
self.loop_bb = loop_bb;
}
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_ => unimplemented!(),
}
}
}