From c8984398174c7e7de5ba4ff84c2884b8d08ffad4 Mon Sep 17 00:00:00 2001
From: Lachlan Sneff <lachlan.sneff@gmail.com>
Date: Thu, 11 Apr 2019 12:07:54 -0700
Subject: [PATCH] Add well placed unwind(allowed) attribute

---
 Cargo.lock                         | 2 ++
 lib/llvm-backend/src/backend.rs    | 6 ++++--
 lib/runtime-core/Cargo.toml        | 1 +
 lib/runtime-core/build.rs          | 5 +++++
 lib/runtime-core/src/lib.rs        | 2 ++
 lib/runtime-core/src/typed_func.rs | 5 ++++-
 lib/runtime/examples/call.rs       | 4 ++--
 7 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 5f111b7b8..a82cca2b3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2274,6 +2274,7 @@ dependencies = [
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.51 (registry+https://github.com/rust-lang/crates.io-index)",
  "nix 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "smallvec 0.6.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasmer-runtime-core 0.2.1",
  "wasmparser 0.28.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -2372,6 +2373,7 @@ dependencies = [
  "nix 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "page_size 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.90 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde-bench 0.0.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_bytes 0.10.5 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/lib/llvm-backend/src/backend.rs b/lib/llvm-backend/src/backend.rs
index f40a6dfb2..176702bc3 100644
--- a/lib/llvm-backend/src/backend.rs
+++ b/lib/llvm-backend/src/backend.rs
@@ -75,10 +75,12 @@ extern "C" {
     fn module_delete(module: *mut LLVMModule);
     fn get_func_symbol(module: *mut LLVMModule, name: *const c_char) -> *const vm::Func;
 
-    fn throw_trap(ty: i32) -> !;
+    fn throw_trap(ty: i32);
 
     /// This should be the same as spliting up the fat pointer into two arguments,
     /// but this is cleaner, I think?
+    #[cfg_attr(nightly, unwind(allowed))]
+    #[allow(improper_ctypes)]
     fn throw_any(data: *mut dyn Any) -> !;
 
     #[allow(improper_ctypes)]
@@ -438,7 +440,7 @@ impl ProtectedCaller for LLVMProtectedCaller {
 
 impl UserTrapper for Placeholder {
     unsafe fn do_early_trap(&self, data: Box<dyn Any>) -> ! {
-        throw_any(Box::leak(data))
+        throw_any(Box::leak(data));
     }
 }
 
diff --git a/lib/runtime-core/Cargo.toml b/lib/runtime-core/Cargo.toml
index 215df568a..41d472626 100644
--- a/lib/runtime-core/Cargo.toml
+++ b/lib/runtime-core/Cargo.toml
@@ -45,6 +45,7 @@ field-offset = "0.1.1"
 
 [build-dependencies]
 blake2b_simd = "0.4.1"
+rustc_version = "0.2.3"
 
 [features]
 debug = []
diff --git a/lib/runtime-core/build.rs b/lib/runtime-core/build.rs
index e91238bc6..38071e31c 100644
--- a/lib/runtime-core/build.rs
+++ b/lib/runtime-core/build.rs
@@ -23,4 +23,9 @@ fn main() {
     f_out
         .write_all(hash_string.as_bytes())
         .expect("Could not write to file for wasmer hash value");
+
+    // Enable "nightly" cfg if the current compiler is nightly.
+    if rustc_version::version_meta().unwrap().channel == rustc_version::Channel::Nightly {
+        println!("cargo:rustc-cfg=nightly");
+    }
 }
diff --git a/lib/runtime-core/src/lib.rs b/lib/runtime-core/src/lib.rs
index d7ef274fd..a43a4c63a 100644
--- a/lib/runtime-core/src/lib.rs
+++ b/lib/runtime-core/src/lib.rs
@@ -1,3 +1,5 @@
+#![cfg_attr(nightly, feature(unwind_attributes))]
+
 #[cfg(test)]
 #[macro_use]
 extern crate field_offset;
diff --git a/lib/runtime-core/src/typed_func.rs b/lib/runtime-core/src/typed_func.rs
index 2ca67dba5..d18055ba1 100644
--- a/lib/runtime-core/src/typed_func.rs
+++ b/lib/runtime-core/src/typed_func.rs
@@ -339,11 +339,14 @@ macro_rules! impl_traits {
             fn to_raw(&self) -> NonNull<vm::Func> {
                 assert_eq!(mem::size_of::<Self>(), 0, "you cannot use a closure that captures state for `Func`.");
 
+                /// This is required for the llvm backend to be able to unwind through this function.
+                #[cfg_attr(nightly, unwind(allowed))]
                 extern fn wrap<$( $x: WasmExternType, )* Rets: WasmTypeList, Trap: TrapEarly<Rets>, FN: Fn( &mut Ctx $( ,$x )* ) -> Trap>( ctx: &mut Ctx $( ,$x: $x )* ) -> Rets::CStruct {
                     let f: FN = unsafe { mem::transmute_copy(&()) };
 
                     let err = match panic::catch_unwind(panic::AssertUnwindSafe(|| {
-                        f( ctx $( ,$x )* ).report()
+                        let res = f( ctx $( ,$x )* ).report();
+                        res
                     })) {
                         Ok(Ok(returns)) => return returns.into_c_struct(),
                         Ok(Err(err)) => err,
diff --git a/lib/runtime/examples/call.rs b/lib/runtime/examples/call.rs
index 12f149062..894fa4ab1 100644
--- a/lib/runtime/examples/call.rs
+++ b/lib/runtime/examples/call.rs
@@ -59,9 +59,9 @@ fn main() -> Result<(), error::Error> {
       },
     })?;
 
-    let foo: Func<(), i32> = instance.func("dbz")?;
+    let foo = instance.dyn_func("dbz")?;
 
-    let result = foo.call();
+    let result = foo.call(&[]);
 
     println!("result: {:?}", result);