From ba79eeaad7ab2c27984114252eead54d76700beb Mon Sep 17 00:00:00 2001
From: Benjamin Saunders <ben.e.saunders@gmail.com>
Date: Fri, 25 Oct 2019 19:26:19 -0700
Subject: [PATCH] Helper macro for including precompiled SPIR-V

Should help suppress the temptation to court UB via naive
include_bytes. Implementation placed in the root because macros are
always imported via the root and it'd be weird for the returned type
to not be beside it.
---
 ash/src/lib.rs               | 27 +++++++++++++++++++++++++++
 ash/src/util.rs              |  4 ++++
 examples/src/bin/triangle.rs | 16 +++++-----------
 3 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/ash/src/lib.rs b/ash/src/lib.rs
index 832cc96f0..d68e532a0 100644
--- a/ash/src/lib.rs
+++ b/ash/src/lib.rs
@@ -52,9 +52,36 @@ impl<'r, T> RawPtr<T> for Option<&'r T> {
     }
 }
 
+/// Include correctly aligned and typed precompiled SPIR-V
+///
+/// Does not account for endianness mismatches between the SPIR-V file and the target. See
+/// `util::read_spv` for a more general solution.
+#[macro_export]
+macro_rules! include_spv {
+    ($path:expr) => {
+        &$crate::util::Align4(*include_bytes!($path)) as &$crate::Spirv
+    };
+}
+
+/// Type returned by `include_spv`, convertible to `&[u32]`
+///
+/// The definition of this type is unstable.
+pub type Spirv = util::Align4<[u8]>;
+
+impl std::ops::Deref for Spirv {
+    type Target = [u32];
+    fn deref(&self) -> &[u32] {
+        #[allow(clippy::cast_ptr_alignment)]
+        unsafe {
+            std::slice::from_raw_parts(self.0.as_ptr() as *const u32, self.0.len() / 4)
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::vk;
+
     #[test]
     fn test_ptr_chains() {
         let mut variable_pointers = vk::PhysicalDeviceVariablePointerFeatures::builder();
diff --git a/ash/src/util.rs b/ash/src/util.rs
index 48591d85c..e8ab9273a 100644
--- a/ash/src/util.rs
+++ b/ash/src/util.rs
@@ -136,3 +136,7 @@ pub fn read_spv<R: io::Read + io::Seek>(x: &mut R) -> io::Result<Vec<u32>> {
     }
     Ok(result)
 }
+
+#[repr(align(4))]
+#[doc(hidden)]
+pub struct Align4<T: ?Sized>(pub T);
diff --git a/examples/src/bin/triangle.rs b/examples/src/bin/triangle.rs
index 86ca5ed6b..5ec0c9a53 100644
--- a/examples/src/bin/triangle.rs
+++ b/examples/src/bin/triangle.rs
@@ -1,9 +1,8 @@
 use ash::util::*;
-use ash::vk;
+use ash::{include_spv, vk, Spirv};
 use examples::*;
 use std::default::Default;
 use std::ffi::CString;
-use std::io::Cursor;
 use std::mem;
 use std::mem::align_of;
 
@@ -198,17 +197,12 @@ fn main() {
         base.device
             .bind_buffer_memory(vertex_input_buffer, vertex_input_buffer_memory, 0)
             .unwrap();
-        let mut vertex_spv_file =
-            Cursor::new(&include_bytes!("../../shader/triangle/vert.spv")[..]);
-        let mut frag_spv_file = Cursor::new(&include_bytes!("../../shader/triangle/frag.spv")[..]);
 
-        let vertex_code =
-            read_spv(&mut vertex_spv_file).expect("Failed to read vertex shader spv file");
-        let vertex_shader_info = vk::ShaderModuleCreateInfo::builder().code(&vertex_code);
+        const VERTEX_CODE: &Spirv = include_spv!("../../shader/triangle/vert.spv");
+        let vertex_shader_info = vk::ShaderModuleCreateInfo::builder().code(VERTEX_CODE);
 
-        let frag_code =
-            read_spv(&mut frag_spv_file).expect("Failed to read fragment shader spv file");
-        let frag_shader_info = vk::ShaderModuleCreateInfo::builder().code(&frag_code);
+        const FRAG_CODE: &Spirv = include_spv!("../../shader/triangle/frag.spv");
+        let frag_shader_info = vk::ShaderModuleCreateInfo::builder().code(FRAG_CODE);
 
         let vertex_shader_module = base
             .device