From a29303dedd4face76b2f58ebc767f2013e8c7d13 Mon Sep 17 00:00:00 2001
From: Nick Fitzgerald <fitzgen@gmail.com>
Date: Tue, 29 Oct 2019 14:24:36 -0700
Subject: [PATCH] Expand the muli-value example for wasmtime-api to use many
 return values

This should exercise the Rust-calling-Wasm code path for when there are more
return values than fit into return registers.
---
 crates/api/examples/multi.rs   |  47 ++++++++++++++++++++++++++++-----
 crates/api/examples/multi.wasm | Bin 49 -> 114 bytes
 crates/api/examples/multi.wat  |  15 +++++++++++
 3 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/crates/api/examples/multi.rs b/crates/api/examples/multi.rs
index 9506c18ebe..e3d35c296e 100644
--- a/crates/api/examples/multi.rs
+++ b/crates/api/examples/multi.rs
@@ -51,19 +51,22 @@ fn main() -> Result<()> {
             .context("Error instantiating module!")?,
     );
 
-    // Extract export.
+    // Extract exports.
     println!("Extracting export...");
     let exports = Ref::map(instance.borrow(), |instance| instance.exports());
     ensure!(!exports.is_empty(), "Error accessing exports!");
-    let run_func = exports[0].func().context("Error accessing exports!")?;
+    let g = exports[0].func().context("> Error accessing export $g!")?;
+    let round_trip_many = exports[1]
+        .func()
+        .context("> Error accessing export $round_trip_many")?;
 
-    // Call.
-    println!("Calling export...");
+    // Call `$g`.
+    println!("Calling export \"g\"...");
     let args = vec![Val::I32(1), Val::I64(3)];
-    let results = run_func
+    let results = g
         .borrow()
         .call(&args)
-        .map_err(|e| format_err!("> Error calling function: {:?}", e))?;
+        .map_err(|e| format_err!("> Error calling g! {:?}", e))?;
 
     println!("Printing result...");
     println!("> {} {}", results[0].i64(), results[1].i32());
@@ -71,6 +74,38 @@ fn main() -> Result<()> {
     debug_assert_eq!(results[0].i64(), 4);
     debug_assert_eq!(results[1].i32(), 2);
 
+    // Call `$round_trip_many`.
+    println!("Calling export \"round_trip_many\"...");
+    let args = vec![
+        Val::I64(0),
+        Val::I64(1),
+        Val::I64(2),
+        Val::I64(3),
+        Val::I64(4),
+        Val::I64(5),
+        Val::I64(6),
+        Val::I64(7),
+        Val::I64(8),
+        Val::I64(9),
+    ];
+    let results = round_trip_many
+        .borrow()
+        .call(&args)
+        .map_err(|e| format_err!("> Error calling round_trip_many! {:?}", e))?;
+
+    println!("Printing result...");
+    print!(">");
+    for r in results.iter() {
+        print!(" {}", r.i64());
+    }
+    println!();
+
+    debug_assert_eq!(results.len(), 10);
+    debug_assert!(args
+        .iter()
+        .zip(results.iter())
+        .all(|(a, r)| a.i64() == r.i64()));
+
     // Shut down.
     println!("Shutting down...");
     drop(store);
diff --git a/crates/api/examples/multi.wasm b/crates/api/examples/multi.wasm
index 2b117daa8628f0fb9fe3e69d508571f718f81b12..9684f9fa1d998c4a3c10f104e634f80f8c454b8c 100644
GIT binary patch
literal 114
zcmYkuy9$Fq6a>(@v&LtURHk(NG8IHgp%EWNn%!R)EP|&x=(foKSjCpX(}y<qf44F=
s*Z??3Sn{Tgu;=<c=Dyk2&(ciY`~&lvDFoRIMR`S(Q>2GtB}$bQCvb}wn*aa+

literal 49
zcmV~$u@QhE5CFluXHW(bN}x1NBr-CG*4^d)UIB|&>=kRrAwG~o&a4w_wJ;cV+7G1c
B1rPuL

diff --git a/crates/api/examples/multi.wat b/crates/api/examples/multi.wat
index f26a857e17..cacd95504a 100644
--- a/crates/api/examples/multi.wat
+++ b/crates/api/examples/multi.wat
@@ -4,4 +4,19 @@
   (func $g (export "g") (param i32 i64) (result i64 i32)
     (call $f (local.get 0) (local.get 1))
   )
+
+  (func $round_trip_many
+        (export "round_trip_many")
+        (param i64 i64 i64 i64 i64 i64 i64 i64 i64 i64)
+        (result i64 i64 i64 i64 i64 i64 i64 i64 i64 i64)
+    local.get 0
+    local.get 1
+    local.get 2
+    local.get 3
+    local.get 4
+    local.get 5
+    local.get 6
+    local.get 7
+    local.get 8
+    local.get 9)
 )