Support the Tail Call Proposal

CHANGELOG.md

@@ -5,6 +5,9 @@
 
 ### Added
 
+* Added support for the WebAssembly `Tail Call` proposal.
+  [#4111](https://github.com/rustwasm/wasm-bindgen/pull/4111)
+
 * Add bindings for `RTCPeerConnection.setConfiguration(RTCConfiguration)` method.
   [#4105](https://github.com/rustwasm/wasm-bindgen/pull/4105)
 
@@ -204,7 +207,7 @@ Released 2024-08-13
 
 * Fix MDN links to static interface methods.
   [#4010](https://github.com/rustwasm/wasm-bindgen/pull/4010)
- 
+
 * Fixed Deno support.
   [#3990](https://github.com/rustwasm/wasm-bindgen/pull/3990)
 

crates/cli-support/Cargo.toml

@@ -22,7 +22,7 @@ serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 tempfile = "3.0"
 unicode-ident = "1.0.5"
-walrus = "0.21"
+walrus = "0.21.2"
 wasm-bindgen-externref-xform = { path = '../externref-xform', version = '=0.2.93' }
 wasm-bindgen-multi-value-xform = { path = '../multi-value-xform', version = '=0.2.93' }
 wasm-bindgen-shared = { path = "../shared", version = '=0.2.93' }

crates/cli-support/src/descriptors.rs

@@ -199,6 +199,12 @@ impl WasmBindgenDescriptorsSection {
                     self.found = true;
                 }
             }
+
+            fn visit_return_call(&mut self, instr: &walrus::ir::ReturnCall) {
+                if instr.func == self.wbindgen_describe_closure {
+                    self.found = true;
+                }
+            }
         }
 
         struct UpdateDescribeClosure {
@@ -212,6 +218,12 @@ impl WasmBindgenDescriptorsSection {
                     call.func = self.replacement;
                 }
             }
+
+            fn visit_return_call_mut(&mut self, instr: &mut walrus::ir::ReturnCall) {
+                if instr.func == self.wbindgen_describe_closure {
+                    instr.func = self.replacement;
+                }
+            }
         }
     }
 }

crates/cli/Cargo.toml

@@ -31,7 +31,7 @@ serde = { version = "1.0", features = ['derive'] }
 serde_derive = "1.0"
 serde_json = "1.0"
 ureq = { version = "2.7", default-features = false, features = ["brotli", "gzip"] }
-walrus = { version = "0.21", features = ['parallel'] }
+walrus = { version = "0.21.2", features = ['parallel'] }
 wasm-bindgen-cli-support = { path = "../cli-support", version = "=0.2.93" }
 wasm-bindgen-shared = { path = "../shared", version = "=0.2.93" }
 

crates/externref-xform/Cargo.toml

@@ -15,7 +15,7 @@ version = "0.2.93"
 
 [dependencies]
 anyhow = "1.0"
-walrus = "0.21"
+walrus = "0.21.2"
 wasm-bindgen-wasm-conventions = { path = "../wasm-conventions", version = "=0.2.93" }
 
 [dev-dependencies]

crates/externref-xform/src/lib.rs

@@ -722,18 +722,19 @@ impl Transform<'_> {
         impl VisitorMut for Rewrite<'_, '_> {
             fn start_instr_seq_mut(&mut self, seq: &mut InstrSeq) {
                 for i in (0..seq.instrs.len()).rev() {
-                    let call = match &mut seq.instrs[i].0 {
-                        Instr::Call(call) => call,
+                    let func = match &mut seq.instrs[i].0 {
+                        Instr::Call(Call { func }) => func,
+                        Instr::ReturnCall(ReturnCall { func }) => func,
                         _ => continue,
                     };
-                    let intrinsic = match self.xform.intrinsic_map.get(&call.func) {
+                    let intrinsic = match self.xform.intrinsic_map.get(func) {
                         Some(f) => f,
                         None => {
                             // If this wasn't a call of an intrinsic, but it was a
                             // call of one of our old import functions then we
                             // switch the functions we're calling here.
-                            if let Some(f) = self.xform.import_map.get(&call.func) {
-                                call.func = *f;
+                            if let Some(f) = self.xform.import_map.get(func) {
+                                *func = *f;
                             }
                             continue;
                         }
@@ -776,8 +777,8 @@ impl Transform<'_> {
                             seq.instrs
                                 .insert(i, (RefNull { ty }.into(), InstrLocId::default()));
                         }
-                        Intrinsic::DropRef => call.func = self.heap_dealloc,
-                        Intrinsic::CloneRef => call.func = self.clone_ref,
+                        Intrinsic::DropRef => *func = self.heap_dealloc,
+                        Intrinsic::CloneRef => *func = self.clone_ref,
                     }
                 }
             }

crates/multi-value-xform/Cargo.toml

@@ -15,7 +15,7 @@ version = "0.2.93"
 
 [dependencies]
 anyhow = "1.0"
-walrus = "0.21"
+walrus = "0.21.2"
 wasm-bindgen-wasm-conventions = { path = "../wasm-conventions", version = "=0.2.93" }
 
 [dev-dependencies]

crates/threads-xform/Cargo.toml

@@ -15,7 +15,7 @@ version = "0.2.93"
 
 [dependencies]
 anyhow = "1.0"
-walrus = "0.21"
+walrus = "0.21.2"
 wasm-bindgen-wasm-conventions = { path = "../wasm-conventions", version = "=0.2.93" }
 
 [dev-dependencies]

crates/wasm-conventions/Cargo.toml

@@ -13,7 +13,7 @@ version = "0.2.93"
 
 [dependencies]
 leb128 = "0.2"
-walrus = "0.21"
+walrus = "0.21.2"
 # Matching the version `walrus` depends on.
 anyhow = "1.0"
 log = "0.4"

crates/wasm-interpreter/Cargo.toml

@@ -16,7 +16,7 @@ version = "0.2.93"
 [dependencies]
 anyhow = "1.0"
 log = "0.4"
-walrus = "0.21"
+walrus = "0.21.2"
 wasm-bindgen-wasm-conventions = { path = "../wasm-conventions", version = "0.2.93" }
 
 [dev-dependencies]

crates/wasm-interpreter/src/lib.rs

@@ -338,13 +338,14 @@ impl Frame<'_> {
                 stack.pop().unwrap();
             }
 
-            Instr::Call(e) => {
+            Instr::Call(Call { func }) | Instr::ReturnCall(ReturnCall { func }) => {
+                let func = *func;
                 // If this function is calling the `__wbindgen_describe`
                 // function, which we've precomputed the id for, then
                 // it's telling us about the next `u32` element in the
                 // descriptor to return. We "call" the imported function
                 // here by directly inlining it.
-                if Some(e.func) == self.interp.describe_id {
+                if Some(func) == self.interp.describe_id {
                     let val = stack.pop().unwrap();
                     log::debug!("__wbindgen_describe({})", val);
                     self.interp.descriptor.push(val as u32);
@@ -354,7 +355,7 @@ impl Frame<'_> {
                 // slightly different signature. Note that we don't eval the
                 // previous arguments because they shouldn't have any side
                 // effects we're interested in.
-                } else if Some(e.func) == self.interp.describe_closure_id {
+                } else if Some(func) == self.interp.describe_closure_id {
                     let val = stack.pop().unwrap();
                     stack.pop();
                     stack.pop();
@@ -368,7 +369,7 @@ impl Frame<'_> {
                     if self
                         .module
                         .funcs
-                        .get(e.func)
+                        .get(func)
                         .name
                         .as_ref()
                         .is_some_and(|name| {
@@ -380,12 +381,17 @@ impl Frame<'_> {
                         return Ok(());
                     }
 
-                    let ty = self.module.types.get(self.module.funcs.get(e.func).ty());
+                    let ty = self.module.types.get(self.module.funcs.get(func).ty());
                     let args = (0..ty.params().len())
                         .map(|_| stack.pop().unwrap())
                         .collect::<Vec<_>>();
 
-                    self.interp.call(e.func, self.module, &args);
+                    self.interp.call(func, self.module, &args);
+                }
+
+                if let Instr::ReturnCall(_) = instr {
+                    log::debug!("return_call");
+                    self.done = true;
                 }
             }