From 783430e6ae1ccb0bf6265e4ec81f7c1596dd3eb0 Mon Sep 17 00:00:00 2001
From: bjorn3 <bjorn3@users.noreply.github.com>
Date: Sat, 13 Jul 2019 11:38:35 +0200
Subject: [PATCH] Replace {u,i}128_* lang items with __rust_{u,i}128_*
 unmangled functions

The -Zlower-128bit-ops feature is completely broken, as libcore needs
those lang items to compile with this feature, but they are only
provided by compiler_builtins, which itself depends on libcore.
According to rust-lang/rust#58969 the feature never got finished.

This commit removes the associated lang items and replaces them with
normal unmangled functions, when there is no existing intrinsic. This
makes it easier for alternative codegen backends to implement 128bit
integer support.
---
 src/int/addsub.rs | 49 +++++++++++++++++++++++------------------------
 src/int/mul.rs    | 17 +++-------------
 src/int/sdiv.rs   | 11 -----------
 src/int/shift.rs  | 40 ++++++++++----------------------------
 src/int/udiv.rs   | 11 -----------
 src/macros.rs     | 14 --------------
 6 files changed, 37 insertions(+), 105 deletions(-)

diff --git a/src/int/addsub.rs b/src/int/addsub.rs
index e2d5bcb..0a88e2f 100644
--- a/src/int/addsub.rs
+++ b/src/int/addsub.rs
@@ -90,44 +90,43 @@ where
 impl Subo for i128 {}
 impl Subo for u128 {}
 
-u128_lang_items! {
-    #[lang = "i128_add"]
-    pub fn rust_i128_add(a: i128, b: i128) -> i128 {
-        rust_u128_add(a as _, b as _) as _
+intrinsics! {
+    pub extern "C" fn __rust_i128_add(a: i128, b: i128) -> i128 {
+        __rust_u128_add(a as _, b as _) as _
     }
-    #[lang = "i128_addo"]
-    pub fn rust_i128_addo(a: i128, b: i128) -> (i128, bool) {
-        let mut oflow = 0;
-        let r = a.addo(b, &mut oflow);
-        (r, oflow != 0)
-    }
-    #[lang = "u128_add"]
-    pub fn rust_u128_add(a: u128, b: u128) -> u128 {
-        a.add(b)
-    }
-    #[lang = "u128_addo"]
-    pub fn rust_u128_addo(a: u128, b: u128) -> (u128, bool) {
+
+    pub extern "C" fn __rust_i128_addo(a: i128, b: i128) -> (i128, bool) {
         let mut oflow = 0;
         let r = a.addo(b, &mut oflow);
         (r, oflow != 0)
     }
 
-    #[lang = "i128_sub"]
-    pub fn rust_i128_sub(a: i128, b: i128) -> i128 {
-        rust_u128_sub(a as _, b as _) as _
+    pub extern "C" fn __rust_u128_add(a: u128, b: u128) -> u128 {
+        a.add(b)
     }
-    #[lang = "i128_subo"]
-    pub fn rust_i128_subo(a: i128, b: i128) -> (i128, bool) {
+
+    pub extern "C" fn __rust_u128_addo(a: u128, b: u128) -> (u128, bool) {
+        let mut oflow = 0;
+        let r = a.addo(b, &mut oflow);
+        (r, oflow != 0)
+    }
+
+
+    pub extern "C" fn __rust_i128_sub(a: i128, b: i128) -> i128 {
+        __rust_u128_sub(a as _, b as _) as _
+    }
+
+    pub extern "C" fn __rust_i128_subo(a: i128, b: i128) -> (i128, bool) {
         let mut oflow = 0;
         let r = a.subo(b, &mut oflow);
         (r, oflow != 0)
     }
-    #[lang = "u128_sub"]
-    pub fn rust_u128_sub(a: u128, b: u128) -> u128 {
+
+    pub extern "C" fn __rust_u128_sub(a: u128, b: u128) -> u128 {
         a.sub(b)
     }
-    #[lang = "u128_subo"]
-    pub fn rust_u128_subo(a: u128, b: u128) -> (u128, bool) {
+
+    pub extern "C" fn __rust_u128_subo(a: u128, b: u128) -> (u128, bool) {
         let mut oflow = 0;
         let r = a.subo(b, &mut oflow);
         (r, oflow != 0)
diff --git a/src/int/mul.rs b/src/int/mul.rs
index 8df58a2..42f1391 100644
--- a/src/int/mul.rs
+++ b/src/int/mul.rs
@@ -107,25 +107,14 @@ intrinsics! {
     pub extern "C" fn __muloti4(a: i128, b: i128, oflow: &mut i32) -> i128 {
         a.mulo(b, oflow)
     }
-}
 
-u128_lang_items! {
-    #[lang = "i128_mul"]
-    pub fn rust_i128_mul(a: i128, b: i128) -> i128 {
-        __multi3(a, b)
-    }
-    #[lang = "i128_mulo"]
-    pub fn rust_i128_mulo(a: i128, b: i128) -> (i128, bool) {
+    pub extern "C" fn __rust_i128_mulo(a: i128, b: i128) -> (i128, bool) {
         let mut oflow = 0;
         let r = __muloti4(a, b, &mut oflow);
         (r, oflow != 0)
     }
-    #[lang = "u128_mul"]
-    pub fn rust_u128_mul(a: u128, b: u128) -> u128 {
-        __multi3(a as _, b as _) as _
-    }
-    #[lang = "u128_mulo"]
-    pub fn rust_u128_mulo(a: u128, b: u128) -> (u128, bool) {
+
+    pub extern "C" fn __rust_u128_mulo(a: u128, b: u128) -> (u128, bool) {
         let mut oflow = 0;
         let r = a.mulo(b, &mut oflow);
         (r, oflow != 0)
diff --git a/src/int/sdiv.rs b/src/int/sdiv.rs
index ad7f67b..c9e252c 100644
--- a/src/int/sdiv.rs
+++ b/src/int/sdiv.rs
@@ -99,14 +99,3 @@ intrinsics! {
         a.divmod(b, rem, |a, b| __divdi3(a, b))
     }
 }
-
-u128_lang_items! {
-    #[lang = "i128_div"]
-    pub fn rust_i128_div(a: i128, b: i128) -> i128 {
-        __divti3(a, b)
-    }
-    #[lang = "i128_rem"]
-    pub fn rust_i128_rem(a: i128, b: i128) -> i128 {
-        __modti3(a, b)
-    }
-}
diff --git a/src/int/shift.rs b/src/int/shift.rs
index d986222..408f8f3 100644
--- a/src/int/shift.rs
+++ b/src/int/shift.rs
@@ -103,40 +103,20 @@ intrinsics! {
     pub extern "C" fn __lshrti3(a: u128, b: u32) -> u128 {
         a.lshr(b)
     }
-}
 
-u128_lang_items! {
-    #[lang = "i128_shl"]
-    pub fn rust_i128_shl(a: i128, b: u32) -> i128 {
-        __ashlti3(a as _, b) as _
-    }
-    #[lang = "i128_shlo"]
-    pub fn rust_i128_shlo(a: i128, b: u128) -> (i128, bool) {
-        (rust_i128_shl(a, b as _), b >= 128)
-    }
-    #[lang = "u128_shl"]
-    pub fn rust_u128_shl(a: u128, b: u32) -> u128 {
-        __ashlti3(a, b)
-    }
-    #[lang = "u128_shlo"]
-    pub fn rust_u128_shlo(a: u128, b: u128) -> (u128, bool) {
-        (rust_u128_shl(a, b as _), b >= 128)
+    pub extern "C" fn __rust_i128_shlo(a: i128, b: u128) -> (i128, bool) {
+        (__ashlti3(a as _, b as _) as _, b >= 128)
     }
 
-    #[lang = "i128_shr"]
-    pub fn rust_i128_shr(a: i128, b: u32) -> i128 {
-        __ashrti3(a, b)
+    pub extern "C" fn __rust_u128_shlo(a: u128, b: u128) -> (u128, bool) {
+        (__ashlti3(a, b as _), b >= 128)
     }
-    #[lang = "i128_shro"]
-    pub fn rust_i128_shro(a: i128, b: u128) -> (i128, bool) {
-        (rust_i128_shr(a, b as _), b >= 128)
+
+    pub extern "C" fn __rust_i128_shro(a: i128, b: u128) -> (i128, bool) {
+        (__ashrti3(a, b as _), b >= 128)
     }
-    #[lang = "u128_shr"]
-    pub fn rust_u128_shr(a: u128, b: u32) -> u128 {
-        __lshrti3(a, b)
-    }
-    #[lang = "u128_shro"]
-    pub fn rust_u128_shro(a: u128, b: u128) -> (u128, bool) {
-        (rust_u128_shr(a, b as _), b >= 128)
+
+    pub extern "C" fn __rust_u128_shro(a: u128, b: u128) -> (u128, bool) {
+        (__lshrti3(a, b as _), b >= 128)
     }
 }
diff --git a/src/int/udiv.rs b/src/int/udiv.rs
index cdec11d..b393ac6 100644
--- a/src/int/udiv.rs
+++ b/src/int/udiv.rs
@@ -268,14 +268,3 @@ intrinsics! {
         udivmod_inner!(n, d, rem, u128)
     }
 }
-
-u128_lang_items! {
-    #[lang = "u128_div"]
-    pub fn rust_u128_div(a: u128, b: u128) -> u128 {
-        __udivti3(a, b)
-    }
-    #[lang = "u128_rem"]
-    pub fn rust_u128_rem(a: u128, b: u128) -> u128 {
-        __umodti3(a, b)
-    }
-}
diff --git a/src/macros.rs b/src/macros.rs
index 4abdae6..2d11ba6 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -280,17 +280,3 @@ pub mod win64_128bit_abi_hack {
         }
     }
 }
-
-macro_rules! u128_lang_items {
-    ($(
-        #[lang = $lang:tt]
-        pub fn $name:ident( $($argname:ident:  $ty:ty),* ) -> $ret:ty {
-            $($body:tt)*
-        }
-    )*) => ($(
-        #[cfg_attr(not(any(stage0, feature = "no-lang-items")), lang = $lang)]
-        pub fn $name( $($argname:  $ty),* ) -> $ret {
-            $($body)*
-        }
-    )*)
-}