fix(c-api) Cherry-pick manually from wasmerio#1657.

CHANGELOG.md

@@ -1,6 +1,7 @@
 # Changelog
 
 ## **[Unreleased]**
+- [#1657](https://github.com/wasmerio/wasmer/pull/1657) Implement `wasm_trap_t` and `wasm_frame_t` for Wasm C API; add examples in Rust and C of exiting early with a host function.
 - [#1645](https://github.com/wasmerio/wasmer/pull/1645) Move the install script to https://github.com/wasmerio/wasmer-install
 
 ## 1.0.0-alpha3 - 2020-09-14

examples/early_exit.rs

@@ -54,7 +54,7 @@ fn main() -> anyhow::Result<()> {
     };
     let instance = Instance::new(&module, &import_object)?;
 
-    // get the `run` function which we'll use as our entrypoint.
+    // Get the `run` function which we'll use as our entrypoint.
     let run_func: NativeFunc<(i32, i32), i32> =
         instance.exports.get_native_function("run").unwrap();
 
@@ -66,10 +66,10 @@ fn main() -> anyhow::Result<()> {
                 result
             );
         }
-        // we're expecting it to fail.
-        // we attempt to downcast the error into the error type that we were expecting.
+        // We're expecting it to fail.
+        // We attempt to downcast the error into the error type that we were expecting.
         Err(e) => match e.downcast::<ExitCode>() {
-            // we found the exit code used to terminate execution.
+            // We found the exit code used to terminate execution.
             Ok(exit_code) => {
                 println!("Exited early with exit code: {}", exit_code);
                 Ok(())

lib/api/src/lib.rs

@@ -70,8 +70,8 @@ pub use wasmer_compiler::{
 };
 pub use wasmer_compiler::{CpuFeature, Features, Target};
 pub use wasmer_engine::{
-    ChainableNamedResolver, DeserializeError, Engine, InstantiationError, LinkError, NamedResolver,
-    NamedResolverChain, Resolver, RuntimeError, SerializeError,
+    ChainableNamedResolver, DeserializeError, Engine, FrameInfo, InstantiationError, LinkError,
+    NamedResolver, NamedResolverChain, Resolver, RuntimeError, SerializeError,
 };
 pub use wasmer_types::{
     Atomically, Bytes, GlobalInit, LocalFunctionIndex, MemoryView, Pages, ValueType,

lib/engine/src/trap/frame_info.rs

@@ -282,7 +282,7 @@ pub fn register(
 /// each frame is described by this structure.
 ///
 /// [`Trap`]: crate::Trap
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct FrameInfo {
     module_name: String,
     func_index: u32,