From b4200b866aa017dc0f1dd33bd7fccbbf27fb52a7 Mon Sep 17 00:00:00 2001
From: Cassie Jones <code@witchoflight.com>
Date: Fri, 1 Jan 2021 19:36:57 -0500
Subject: [PATCH] [rt] Fix some FFI safety issues

Need #[repr(C)] on a union to make it FFI safe, and need extern "C" on
FFI function pointers.
---
 Cargo.lock    | 2 +-
 rt/src/lib.rs | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 1c11f1f..4a9c04c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -99,7 +99,7 @@ dependencies = [
 
 [[package]]
 name = "ivy"
-version = "0.1.0"
+version = "0.2.0"
 dependencies = [
  "ess",
  "pretty",
diff --git a/rt/src/lib.rs b/rt/src/lib.rs
index 72bf27a..aea68b9 100644
--- a/rt/src/lib.rs
+++ b/rt/src/lib.rs
@@ -1,5 +1,6 @@
 use std::sync::atomic::{Ordering, AtomicU32};
 
+const _STDIN: i32 = 0;
 const _STDOUT: i32 = 1;
 const STDERR: i32 = 2;
 
@@ -36,12 +37,13 @@ pub struct ObjLam {
     tag: ObjTag,
     upvars: u16,
     rc: AtomicU32,
-    func: fn(&ObjLam) -> Obj,
+    func: extern "C" fn(&ObjLam) -> Obj,
     params: u16,
     filled: u16,
 }
 
 #[derive(Clone, Copy)]
+#[repr(C)]
 pub union Obj {
     int: i64,
     header: *mut ObjHeader,
@@ -97,7 +99,7 @@ pub unsafe extern "C" fn ivy_make_int(value: i64) -> Obj {
 }
 
 #[no_mangle]
-pub unsafe extern "C" fn ivy_make_lam(func: fn(&ObjLam) -> Obj, params: u16, upvars: u16) -> Obj {
+pub unsafe extern "C" fn ivy_make_lam(func: extern "C" fn(&ObjLam) -> Obj, params: u16, upvars: u16) -> Obj {
     let size = ObjLam::size_of(params, upvars);
     let box_lam = sys::malloc(size) as *mut ObjLam;
     box_lam.write(ObjLam {
-- 
2.47.0