From 54c8dfb100f5a63e68c28d0255f260f10e0726d1 Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Thu, 3 Oct 2024 23:53:37 -0400
Subject: [PATCH] Add linkage attributes to extern "C" blocks

---
 build.rs          | 4 ++--
 src/ffi_avx2.rs   | 4 ++++
 src/ffi_avx512.rs | 4 ++++
 src/ffi_neon.rs   | 1 +
 src/ffi_sse2.rs   | 4 ++++
 src/ffi_sse41.rs  | 4 ++++
 6 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/build.rs b/build.rs
index af5805d9c..0cf34449b 100644
--- a/build.rs
+++ b/build.rs
@@ -230,6 +230,7 @@ fn build_avx512_assembly() {
 }
 
 fn build_neon_c_intrinsics() {
+    println!("cargo:rustc-cfg=blake3_neon_ffi");
     let mut build = new_build();
     // Note that blake3_neon.c normally depends on the blake3_portable.c
     // for the single-instance compression function, but we expose
@@ -254,7 +255,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         "blake3_avx2_ffi",
         "blake3_avx2_rust",
         "blake3_avx512_ffi",
-        "blake3_neon",
+        "blake3_neon_ffi",
     ];
     for cfg_name in all_cfgs {
         // TODO: Switch this whole file to the new :: syntax when our MSRV reaches 1.77.
@@ -296,7 +297,6 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     if (is_arm() && is_neon())
         || (!is_no_neon() && !is_pure() && is_aarch64() && is_little_endian())
     {
-        println!("cargo:rustc-cfg=blake3_neon");
         build_neon_c_intrinsics();
     }
 
diff --git a/src/ffi_avx2.rs b/src/ffi_avx2.rs
index 33961e9d4..0fc466487 100644
--- a/src/ffi_avx2.rs
+++ b/src/ffi_avx2.rs
@@ -33,6 +33,10 @@ pub unsafe fn hash_many<const N: usize>(
 }
 
 pub mod ffi {
+    #[cfg_attr(
+        blake3_avx2_ffi,
+        link(name = "blake3_sse2_sse41_avx2_assembly", kind = "static")
+    )]
     extern "C" {
         pub fn blake3_hash_many_avx2(
             inputs: *const *const u8,
diff --git a/src/ffi_avx512.rs b/src/ffi_avx512.rs
index 884f48135..4c08b72ee 100644
--- a/src/ffi_avx512.rs
+++ b/src/ffi_avx512.rs
@@ -61,6 +61,10 @@ pub unsafe fn hash_many<const N: usize>(
 }
 
 pub mod ffi {
+    #[cfg_attr(
+        blake3_avx512_ffi,
+        link(name = "blake3_avx512_assembly", kind = "static")
+    )]
     extern "C" {
         pub fn blake3_compress_in_place_avx512(
             cv: *mut u32,
diff --git a/src/ffi_neon.rs b/src/ffi_neon.rs
index 54d07a4de..b8493dae0 100644
--- a/src/ffi_neon.rs
+++ b/src/ffi_neon.rs
@@ -53,6 +53,7 @@ pub extern "C" fn blake3_compress_in_place_portable(
 }
 
 pub mod ffi {
+    #[cfg_attr(blake3_neon_ffi, link(name = "blake3_neon", kind = "static"))]
     extern "C" {
         pub fn blake3_hash_many_neon(
             inputs: *const *const u8,
diff --git a/src/ffi_sse2.rs b/src/ffi_sse2.rs
index 1c5da81f9..353bac0ae 100644
--- a/src/ffi_sse2.rs
+++ b/src/ffi_sse2.rs
@@ -61,6 +61,10 @@ pub unsafe fn hash_many<const N: usize>(
 }
 
 pub mod ffi {
+    #[cfg_attr(
+        blake3_sse2_ffi,
+        link(name = "blake3_sse2_sse41_avx2_assembly", kind = "static")
+    )]
     extern "C" {
         pub fn blake3_compress_in_place_sse2(
             cv: *mut u32,
diff --git a/src/ffi_sse41.rs b/src/ffi_sse41.rs
index 62989c5ec..ff7b62c6e 100644
--- a/src/ffi_sse41.rs
+++ b/src/ffi_sse41.rs
@@ -61,6 +61,10 @@ pub unsafe fn hash_many<const N: usize>(
 }
 
 pub mod ffi {
+    #[cfg_attr(
+        blake3_sse41_ffi,
+        link(name = "blake3_sse2_sse41_avx2_assembly", kind = "static")
+    )]
     extern "C" {
         pub fn blake3_compress_in_place_sse41(
             cv: *mut u32,