[EH] Misc. fixes for EH (#6195)

- Deletes a stray whitespace after `throw_ref`
- Adds missing `makeThrowRef` to `wasm-builder.h`
- Adds a case for `TryTable` in `ControlFlowWalker`

4 files changed, 28 insertions, 18 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index 5ea62c9f2..5e290ebca 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -2018,7 +2018,7 @@ struct PrintExpressionContents
     printMedium(o, "rethrow ");
     printName(curr->target, o);
   }
-  void visitThrowRef(ThrowRef* curr) { printMedium(o, "throw_ref "); }
+  void visitThrowRef(ThrowRef* curr) { printMedium(o, "throw_ref"); }
   void visitNop(Nop* curr) { printMinor(o, "nop"); }
   void visitUnreachable(Unreachable* curr) { printMinor(o, "unreachable"); }
   void visitPop(Pop* curr) {
diff --git a/src/wasm-builder.h b/src/wasm-builder.h
index dd5b498be..a873a7309 100644
--- a/src/wasm-builder.h
+++ b/src/wasm-builder.h
@@ -836,6 +836,12 @@ public:
     ret->finalize();
     return ret;
   }
+  ThrowRef* makeThrowRef(Expression* exnref) {
+    auto* ret = wasm.allocator.alloc<ThrowRef>();
+    ret->exnref = exnref;
+    ret->finalize();
+    return ret;
+  }
   Unreachable* makeUnreachable() { return wasm.allocator.alloc<Unreachable>(); }
   Pop* makePop(Type type) {
     auto* ret = wasm.allocator.alloc<Pop>();
diff --git a/src/wasm-traversal.h b/src/wasm-traversal.h
index 1a458bdf7..f5f25dd1f 100644
--- a/src/wasm-traversal.h
+++ b/src/wasm-traversal.h
@@ -403,7 +403,8 @@ using ExpressionStack = SmallVector<Expression*, 10>;
 
 template<typename SubType, typename VisitorType = Visitor<SubType>>
 struct ControlFlowWalker : public PostWalker<SubType, VisitorType> {
-  ExpressionStack controlFlowStack; // contains blocks, loops, and ifs
+  // contains blocks, loops, ifs, trys, and try_tables
+  ExpressionStack controlFlowStack;
 
   // Uses the control flow stack to find the target of a break to a name
   Expression* findBreakTarget(Name name) {
@@ -420,8 +421,9 @@ struct ControlFlowWalker : public PostWalker<SubType, VisitorType> {
           return curr;
         }
       } else {
-        // an if or try, ignorable
-        assert(curr->template is<If>() || curr->template is<Try>());
+        // an if, try, or try_table, ignorable
+        assert(curr->template is<If>() || curr->template is<Try>() ||
+               curr->template is<TryTable>());
       }
       if (i == 0) {
         return nullptr;
@@ -447,7 +449,8 @@ struct ControlFlowWalker : public PostWalker<SubType, VisitorType> {
       case Expression::Id::BlockId:
       case Expression::Id::IfId:
       case Expression::Id::LoopId:
-      case Expression::Id::TryId: {
+      case Expression::Id::TryId:
+      case Expression::Id::TryTableId: {
         self->pushTask(SubType::doPostVisitControlFlow, currp);
         break;
       }
@@ -461,7 +464,8 @@ struct ControlFlowWalker : public PostWalker<SubType, VisitorType> {
       case Expression::Id::BlockId:
       case Expression::Id::IfId:
       case Expression::Id::LoopId:
-      case Expression::Id::TryId: {
+      case Expression::Id::TryId:
+      case Expression::Id::TryTableId: {
         self->pushTask(SubType::doPreVisitControlFlow, currp);
         break;
       }
diff --git a/test/lit/basic/exception-handling.wast b/test/lit/basic/exception-handling.wast
index cf0e8a62e..b94f89e1a 100644
--- a/test/lit/basic/exception-handling.wast
+++ b/test/lit/basic/exception-handling.wast
@@ -162,7 +162,7 @@
   )
 
   ;; CHECK-TEXT:      (func $try-table-and-throw-ref (type $0)
-  ;; CHECK-TEXT-NEXT:  (throw_ref 
+  ;; CHECK-TEXT-NEXT:  (throw_ref
   ;; CHECK-TEXT-NEXT:   (block $l-catch-all-ref (result exnref)
   ;; CHECK-TEXT-NEXT:    (try_table (catch_all_ref $l-catch-all-ref)
   ;; CHECK-TEXT-NEXT:     (throw $e-i64
@@ -173,7 +173,7 @@
   ;; CHECK-TEXT-NEXT:  )
   ;; CHECK-TEXT-NEXT: )
   ;; CHECK-BIN:      (func $try-table-and-throw-ref (type $0)
-  ;; CHECK-BIN-NEXT:  (throw_ref 
+  ;; CHECK-BIN-NEXT:  (throw_ref
   ;; CHECK-BIN-NEXT:   (block $label$1 (result exnref)
   ;; CHECK-BIN-NEXT:    (try_table (catch_all_ref $label$1)
   ;; CHECK-BIN-NEXT:     (throw $e-i64
@@ -300,7 +300,7 @@
   ;; CHECK-TEXT-NEXT:    (drop
   ;; CHECK-TEXT-NEXT:     (block $l-catch-ref (result exnref)
   ;; CHECK-TEXT-NEXT:      (block $l-catch-all
-  ;; CHECK-TEXT-NEXT:       (throw_ref 
+  ;; CHECK-TEXT-NEXT:       (throw_ref
   ;; CHECK-TEXT-NEXT:        (block $l-catch-all-ref (result exnref)
   ;; CHECK-TEXT-NEXT:         (try_table (catch $e-empty $l-catch) (catch_ref $e-empty $l-catch-ref) (catch_all $l-catch-all) (catch_all_ref $l-catch-all-ref)
   ;; CHECK-TEXT-NEXT:          (call $foo)
@@ -323,7 +323,7 @@
   ;; CHECK-BIN-NEXT:    (drop
   ;; CHECK-BIN-NEXT:     (block $label$3 (result exnref)
   ;; CHECK-BIN-NEXT:      (block $label$4
-  ;; CHECK-BIN-NEXT:       (throw_ref 
+  ;; CHECK-BIN-NEXT:       (throw_ref
   ;; CHECK-BIN-NEXT:        (block $label$5 (result exnref)
   ;; CHECK-BIN-NEXT:         (try_table (catch $e-empty $label$2) (catch_ref $e-empty $label$3) (catch_all $label$4) (catch_all_ref $label$5)
   ;; CHECK-BIN-NEXT:          (call $foo)
@@ -376,7 +376,7 @@
   ;; CHECK-TEXT-NEXT:     (tuple.drop 2
   ;; CHECK-TEXT-NEXT:      (block $l-catch-ref (type $5) (result i32 exnref)
   ;; CHECK-TEXT-NEXT:       (block $l-catch-all
-  ;; CHECK-TEXT-NEXT:        (throw_ref 
+  ;; CHECK-TEXT-NEXT:        (throw_ref
   ;; CHECK-TEXT-NEXT:         (block $l-catch-all-ref (result exnref)
   ;; CHECK-TEXT-NEXT:          (try_table (catch $e-i32 $l-catch) (catch_ref $e-i32 $l-catch-ref) (catch_all $l-catch-all) (catch_all_ref $l-catch-all-ref)
   ;; CHECK-TEXT-NEXT:           (call $foo)
@@ -403,7 +403,7 @@
   ;; CHECK-BIN-NEXT:     (local.set $0
   ;; CHECK-BIN-NEXT:      (block $label$3 (type $5) (result i32 exnref)
   ;; CHECK-BIN-NEXT:       (block $label$4
-  ;; CHECK-BIN-NEXT:        (throw_ref 
+  ;; CHECK-BIN-NEXT:        (throw_ref
   ;; CHECK-BIN-NEXT:         (block $label$5 (result exnref)
   ;; CHECK-BIN-NEXT:          (try_table (catch $e-i32 $label$2) (catch_ref $e-i32 $label$3) (catch_all $label$4) (catch_all_ref $label$5)
   ;; CHECK-BIN-NEXT:           (call $foo)
@@ -474,7 +474,7 @@
   ;; CHECK-TEXT-NEXT:     (tuple.drop 3
   ;; CHECK-TEXT-NEXT:      (block $l-catch-ref (type $2) (result i32 i64 exnref)
   ;; CHECK-TEXT-NEXT:       (block $l-catch-all
-  ;; CHECK-TEXT-NEXT:        (throw_ref 
+  ;; CHECK-TEXT-NEXT:        (throw_ref
   ;; CHECK-TEXT-NEXT:         (block $l-catch-all-ref (result exnref)
   ;; CHECK-TEXT-NEXT:          (try_table (catch $e-i32-i64 $l-catch) (catch_ref $e-i32-i64 $l-catch-ref) (catch_all $l-catch-all) (catch_all_ref $l-catch-all-ref)
   ;; CHECK-TEXT-NEXT:           (call $foo)
@@ -504,7 +504,7 @@
   ;; CHECK-BIN-NEXT:     (local.set $0
   ;; CHECK-BIN-NEXT:      (block $label$3 (type $2) (result i32 i64 exnref)
   ;; CHECK-BIN-NEXT:       (block $label$4
-  ;; CHECK-BIN-NEXT:        (throw_ref 
+  ;; CHECK-BIN-NEXT:        (throw_ref
   ;; CHECK-BIN-NEXT:         (block $label$5 (result exnref)
   ;; CHECK-BIN-NEXT:          (try_table (catch $e-i32-i64 $label$2) (catch_ref $e-i32-i64 $label$3) (catch_all $label$4) (catch_all_ref $label$5)
   ;; CHECK-BIN-NEXT:           (call $foo)
@@ -754,7 +754,7 @@
 ;; CHECK-BIN-NODEBUG-NEXT: )
 
 ;; CHECK-BIN-NODEBUG:      (func $4 (type $0)
-;; CHECK-BIN-NODEBUG-NEXT:  (throw_ref 
+;; CHECK-BIN-NODEBUG-NEXT:  (throw_ref
 ;; CHECK-BIN-NODEBUG-NEXT:   (block $label$1 (result exnref)
 ;; CHECK-BIN-NODEBUG-NEXT:    (try_table (catch_all_ref $label$1)
 ;; CHECK-BIN-NODEBUG-NEXT:     (throw $tag$1
@@ -836,7 +836,7 @@
 ;; CHECK-BIN-NODEBUG-NEXT:    (drop
 ;; CHECK-BIN-NODEBUG-NEXT:     (block $label$3 (result exnref)
 ;; CHECK-BIN-NODEBUG-NEXT:      (block $label$4
-;; CHECK-BIN-NODEBUG-NEXT:       (throw_ref 
+;; CHECK-BIN-NODEBUG-NEXT:       (throw_ref
 ;; CHECK-BIN-NODEBUG-NEXT:        (block $label$5 (result exnref)
 ;; CHECK-BIN-NODEBUG-NEXT:         (try_table (catch $tag$4 $label$2) (catch_ref $tag$4 $label$3) (catch_all $label$4) (catch_all_ref $label$5)
 ;; CHECK-BIN-NODEBUG-NEXT:          (call $0)
@@ -863,7 +863,7 @@
 ;; CHECK-BIN-NODEBUG-NEXT:     (local.set $0
 ;; CHECK-BIN-NODEBUG-NEXT:      (block $label$3 (type $5) (result i32 exnref)
 ;; CHECK-BIN-NODEBUG-NEXT:       (block $label$4
-;; CHECK-BIN-NODEBUG-NEXT:        (throw_ref 
+;; CHECK-BIN-NODEBUG-NEXT:        (throw_ref
 ;; CHECK-BIN-NODEBUG-NEXT:         (block $label$5 (result exnref)
 ;; CHECK-BIN-NODEBUG-NEXT:          (try_table (catch $tag$0 $label$2) (catch_ref $tag$0 $label$3) (catch_all $label$4) (catch_all_ref $label$5)
 ;; CHECK-BIN-NODEBUG-NEXT:           (call $0)
@@ -909,7 +909,7 @@
 ;; CHECK-BIN-NODEBUG-NEXT:     (local.set $0
 ;; CHECK-BIN-NODEBUG-NEXT:      (block $label$3 (type $2) (result i32 i64 exnref)
 ;; CHECK-BIN-NODEBUG-NEXT:       (block $label$4
-;; CHECK-BIN-NODEBUG-NEXT:        (throw_ref 
+;; CHECK-BIN-NODEBUG-NEXT:        (throw_ref
 ;; CHECK-BIN-NODEBUG-NEXT:         (block $label$5 (result exnref)
 ;; CHECK-BIN-NODEBUG-NEXT:          (try_table (catch $tag$2 $label$2) (catch_ref $tag$2 $label$3) (catch_all $label$4) (catch_all_ref $label$5)
 ;; CHECK-BIN-NODEBUG-NEXT:           (call $0)