From da91cbbd5bb8cb925dee4a5c6ab6d66588cb2c8f Mon Sep 17 00:00:00 2001
From: Johannes Stoelp <johannes.stoelp@gmail.com>
Date: Sun, 25 Sep 2022 00:00:24 +0200
Subject: added external fn putchard, and added link flag to export symbols
 from elf file

---
 .cargo/config |  2 ++
 src/main.rs   | 11 ++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 .cargo/config

diff --git a/.cargo/config b/.cargo/config
new file mode 100644
index 0000000..52e8b72
--- /dev/null
+++ b/.cargo/config
@@ -0,0 +1,2 @@
+[build]
+rustflags = ["-C", "link-args=-rdynamic"]
diff --git a/src/main.rs b/src/main.rs
index 945d588..b660416 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,7 +7,16 @@ use llvm_kaleidoscope_rs::{
 };
 
 use std::collections::HashMap;
-use std::io::Read;
+use std::io::{Read, Write};
+
+#[no_mangle]
+#[inline(never)]
+pub extern "C" fn putchard(c: libc::c_double) -> f64 {
+    std::io::stdout()
+        .write(&[c as u8])
+        .expect("Failed to write to stdout!");
+    0f64
+}
 
 fn main_loop<I>(mut parser: Parser<I>)
 where
-- 
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