Merge pull request #41 from kariya-mitsuru/fix-label-handling

Fix label handling
rhysd · Jul 13, 2020 · af89176 · af89176
2 parents eb62526 + c2e422d
commit af89176
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Showing 2 changed files with 18 additions and 23 deletions.
diff --git a/wain-exec/src/runtime.rs b/wain-exec/src/runtime.rs
@@ -472,46 +472,43 @@ impl<'m, 's, I: Importer> Execute<'m, 's, I> for ast::Instruction {
             // Control instructions
             // https://webassembly.github.io/spec/core/exec/instructions.html#exec-block
             Block { ty, body } => {
-                let label = runtime.stack.push_label(*ty);
+                let label = runtime.stack.push_label();
                 match body.execute(runtime)? {
                     ExecState::Continue => {}
                     ExecState::Ret => return Ok(ExecState::Ret),
-                    ExecState::Breaking(0) => {}
+                    ExecState::Breaking(0) => runtime.stack.pop_label(&label, ty.is_some()),
                     ExecState::Breaking(level) => return Ok(ExecState::Breaking(level - 1)),
                 }
-                runtime.stack.pop_label(label);
             }
             // https://webassembly.github.io/spec/core/exec/instructions.html#exec-loop
-            Loop { ty, body } => loop {
-                // Note: Difference between block and loop is the position on breaking. When reaching
-                // to the end of instruction sequence, loop instruction ends execution of subsequence.
-                let label = runtime.stack.push_label(*ty);
-                match body.execute(runtime)? {
-                    ExecState::Continue => {
-                        runtime.stack.pop_label(label);
-                        break;
+            Loop { body, .. } => {
+                let label = runtime.stack.push_label();
+                loop {
+                    // Note: Difference between block and loop is the position on breaking. When reaching
+                    // to the end of instruction sequence, loop instruction ends execution of subsequence.
+                    match body.execute(runtime)? {
+                        ExecState::Continue => break,
+                        ExecState::Ret => return Ok(ExecState::Ret),
+                        ExecState::Breaking(0) => runtime.stack.pop_label(&label, false),
+                        ExecState::Breaking(level) => return Ok(ExecState::Breaking(level - 1)),
                     }
-                    ExecState::Ret => return Ok(ExecState::Ret),
-                    ExecState::Breaking(0) => continue,
-                    ExecState::Breaking(level) => return Ok(ExecState::Breaking(level - 1)),
                 }
-            },
+            }
             // https://webassembly.github.io/spec/core/exec/instructions.html#exec-if
             If {
                 ty,
                 then_body,
                 else_body,
             } => {
                 let cond: i32 = runtime.stack.pop();
-                let label = runtime.stack.push_label(*ty);
+                let label = runtime.stack.push_label();
                 let insns = if cond != 0 { then_body } else { else_body };
                 match insns.execute(runtime)? {
                     ExecState::Continue => {}
                     ExecState::Ret => return Ok(ExecState::Ret),
-                    ExecState::Breaking(0) => {}
+                    ExecState::Breaking(0) => runtime.stack.pop_label(&label, ty.is_some()),
                     ExecState::Breaking(level) => return Ok(ExecState::Breaking(level - 1)),
                 }
-                runtime.stack.pop_label(label);
             }
             // https://webassembly.github.io/spec/core/exec/instructions.html#exec-unreachable
             Unreachable => return Err(Trap::new(TrapReason::ReachUnreachable, self.start)),

diff --git a/wain-exec/src/stack.rs b/wain-exec/src/stack.rs
@@ -192,17 +192,16 @@ impl Stack {
         self.types.truncate(type_idx);
     }
 
-    pub fn push_label(&self, ty: Option<ValType>) -> Label {
+    pub fn push_label(&self) -> Label {
         Label {
             addr: self.top_addr(),
             type_idx: self.top_idx(),
-            has_result: ty.is_some(),
         }
     }
 
-    pub fn pop_label(&mut self, label: Label) {
+    pub fn pop_label(&mut self, label: &Label, has_result: bool) {
         // Part of 'br' instruction: https://webassembly.github.io/spec/core/exec/instructions.html#exec-br
-        if label.has_result {
+        if has_result {
             let v: Value = self.pop();
             self.restore(label.addr, label.type_idx);
             self.push(v);
@@ -261,7 +260,6 @@ impl CallFrame {
 pub struct Label {
     addr: usize,
     type_idx: usize,
-    has_result: bool,
 }
 
 #[cfg(test)]