Fix printing of bulk array ops (#6387)

When the bulk array ops had unreachable or null array types, they were replaced
with blocks, but not using the correct code that also prints all their children
as dropped followed by an unreachable. This meant that the text output in those
cases did not parse as a valid module.

Fix the bug. A follow-up PR will simplify the code to prevent similar bugs from
occurring in the future.

4 files changed, 212 insertions, 66 deletions

diff --git a/src/passes/Print.cpp b/src/passes/Print.cpp
index b0c83c437..af91a3194 100644
--- a/src/passes/Print.cpp
+++ b/src/passes/Print.cpp
@@ -289,6 +289,25 @@ struct PrintSExpression : public UnifiedExpressionVisitor<PrintSExpression> {
   void visitArrayGet(ArrayGet* curr) {
     maybePrintUnreachableOrNullReplacement(curr, curr->ref->type);
   }
+  void visitArrayCopy(ArrayCopy* curr) {
+    if (curr->srcRef->type == Type::unreachable ||
+        curr->destRef->type == Type::unreachable ||
+        curr->srcRef->type.isNull() || curr->destRef->type.isNull()) {
+      maybePrintUnreachableOrNullReplacement(curr, Type::unreachable);
+      return;
+    }
+    visitExpression(curr);
+  }
+  void visitArrayFill(ArrayFill* curr) {
+    maybePrintUnreachableOrNullReplacement(curr, curr->ref->type);
+  }
+  void visitArrayInitData(ArrayInitData* curr) {
+    maybePrintUnreachableOrNullReplacement(curr, curr->ref->type);
+  }
+  void visitArrayInitElem(ArrayInitElem* curr) {
+    maybePrintUnreachableOrNullReplacement(curr, curr->ref->type);
+  }
+
   // Module-level visitors
   void handleSignature(HeapType curr, Name name = Name());
   void visitExport(Export* curr);
diff --git a/test/lit/passes/gufa-refs.wast b/test/lit/passes/gufa-refs.wast
index e6e5d0bde..4be45e4ca 100644
--- a/test/lit/passes/gufa-refs.wast
+++ b/test/lit/passes/gufa-refs.wast
@@ -5632,11 +5632,20 @@
   (data $0 "")
 
   ;; CHECK:      (func $test (type $0)
-  ;; CHECK-NEXT:  (block
+  ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayInitData we can't emit)
+  ;; CHECK-NEXT:   (drop
+  ;; CHECK-NEXT:    (unreachable)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (drop
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (drop
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:   (drop
+  ;; CHECK-NEXT:    (i32.const 1)
+  ;; CHECK-NEXT:   )
   ;; CHECK-NEXT:   (unreachable)
-  ;; CHECK-NEXT:   (i32.const 0)
-  ;; CHECK-NEXT:   (i32.const 0)
-  ;; CHECK-NEXT:   (i32.const 1)
   ;; CHECK-NEXT:  )
   ;; CHECK-NEXT: )
   (func $test
diff --git a/test/lit/passes/type-generalizing.wast b/test/lit/passes/type-generalizing.wast
index 2c1714a46..f927086de 100644
--- a/test/lit/passes/type-generalizing.wast
+++ b/test/lit/passes/type-generalizing.wast
@@ -1383,12 +1383,23 @@
  ;; CHECK:      (func $array-copy-impossible-dest (type $0)
  ;; CHECK-NEXT:  (local $dest nullref)
  ;; CHECK-NEXT:  (local $src anyref)
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (local.get $dest)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (local.get $src)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayCopy we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $dest)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $src)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-copy-impossible-dest
@@ -1408,12 +1419,23 @@
  ;; CHECK:      (func $array-copy-impossible-src (type $0)
  ;; CHECK-NEXT:  (local $dest anyref)
  ;; CHECK-NEXT:  (local $src nullref)
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (local.get $dest)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (local.get $src)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayCopy we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $dest)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $src)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-copy-impossible-src
@@ -1433,12 +1455,23 @@
  ;; CHECK:      (func $array-copy-impossible-both (type $0)
  ;; CHECK-NEXT:  (local $dest nullref)
  ;; CHECK-NEXT:  (local $src nullref)
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (local.get $dest)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (local.get $src)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayCopy we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $dest)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $src)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-copy-impossible-both
@@ -1481,11 +1514,20 @@
  ;; CHECK:      (func $array-fill-impossible (type $0)
  ;; CHECK-NEXT:  (local $ref nullref)
  ;; CHECK-NEXT:  (local $val anyref)
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (local.get $ref)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (local.get $val)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayFill we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $ref)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $val)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-fill-impossible
@@ -1522,11 +1564,20 @@
 
  ;; CHECK:      (func $array-init-data-impossible (type $0)
  ;; CHECK-NEXT:  (local $ref nullref)
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (local.get $ref)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayInitData we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $ref)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-init-data-impossible
@@ -1562,11 +1613,20 @@
 
  ;; CHECK:      (func $array-init-elem-impossible (type $0)
  ;; CHECK-NEXT:  (local $ref nullref)
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (local.get $ref)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayInitElem we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (local.get $ref)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-init-elem-impossible
diff --git a/test/lit/passes/unsubtyping.wast b/test/lit/passes/unsubtyping.wast
index 8408c2e7d..204b76ef7 100644
--- a/test/lit/passes/unsubtyping.wast
+++ b/test/lit/passes/unsubtyping.wast
@@ -1441,19 +1441,41 @@
  ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayCopy we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (unreachable)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (array.new_fixed $sub-array 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:   (unreachable)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (array.new_fixed $sub-array 0)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (array.new_fixed $super-array 0)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (ref.null none)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayCopy we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (array.new_fixed $super-array 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (ref.null none)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-copy
@@ -1503,17 +1525,35 @@
  ;; CHECK-NEXT:   (struct.new_default $sub)
  ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayFill we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (unreachable)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (struct.new_default $sub)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:   (unreachable)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (struct.new_default $sub)
- ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (ref.null none)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (struct.new_default $sub)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayFill we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (ref.null none)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (struct.new_default $sub)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-fill
@@ -1564,17 +1604,35 @@
  ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayInitElem we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (unreachable)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
  ;; CHECK-NEXT:   (unreachable)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
  ;; CHECK-NEXT:  )
- ;; CHECK-NEXT:  (block
- ;; CHECK-NEXT:   (ref.null none)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
- ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  (block ;; (replaces unreachable ArrayInitElem we can't emit)
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (ref.null none)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (drop
+ ;; CHECK-NEXT:    (i32.const 0)
+ ;; CHECK-NEXT:   )
+ ;; CHECK-NEXT:   (unreachable)
  ;; CHECK-NEXT:  )
  ;; CHECK-NEXT: )
  (func $array-init-elem