Fix possible-contents.h for `array.new_{data,elem}` (#5232)

* Update MemoryPacking for array.new_data

The MemoryPacking pass looks at all instructions that reference memory segments
to determine how they can be optimized. #5214 introduced a new instruction that
references memory segments, array.new_data, but did not update MemoryPacking
accordingly. This omission meant that MemoryPacking could produce invalid or
misoptimized modules in the presence of array.new_data.

Fix the problem by making MemoryPacking aware of array.new_data. Consider
array.new_data when determining whether a segment is used and update
array.new_data to reflect the new, optimized segment numberings afterward. To
keep things simple, do not try to split any segment that is referred to by
a array.new_data instruction.

* fix

* Add test explanations

* Fix possible-contents.h for `array.new_{data,elem}`

This code was not properly updated in #5214, so GUFA would incorrectly optimize
out `array.new_data` and `array.new_elem` instructions. Fix the problem by
making these instructions data flow roots.

* fix

* move tests

2 files changed, 71 insertions, 0 deletions

diff --git a/src/ir/possible-contents.cpp b/src/ir/possible-contents.cpp
index 0c4e28568..35e87175a 100644
--- a/src/ir/possible-contents.cpp
+++ b/src/ir/possible-contents.cpp
@@ -900,6 +900,7 @@ struct InfoCollector
     if (curr->type == Type::unreachable) {
       return;
     }
+    addRoot(curr, PossibleContents::exactType(curr->type));
     auto heapType = curr->type.getHeapType();
     switch (curr->op) {
       case NewData: {
diff --git a/test/lit/passes/gufa-refs.wast b/test/lit/passes/gufa-refs.wast
index e5df2afd4..fc01dd481 100644
--- a/test/lit/passes/gufa-refs.wast
+++ b/test/lit/passes/gufa-refs.wast
@@ -5393,3 +5393,73 @@
     )
   )
 )
+
+
+;; Check that array.new_data and array.new_seg are handled properly.
+(module
+  ;; CHECK:      (type $array-i8 (array_subtype i8 data))
+  (type $array-i8 (array i8))
+  ;; CHECK:      (type $array-funcref (array_subtype funcref data))
+  (type $array-funcref (array funcref))
+  ;; CHECK:      (type $ref|$array-i8|_ref|$array-funcref|_=>_none (func_subtype (param (ref $array-i8) (ref $array-funcref)) func))
+
+  ;; CHECK:      (data "hello")
+  (data "hello")
+  ;; CHECK:      (elem func $test)
+  (elem func $test)
+
+  ;; CHECK:      (export "test" (func $test))
+
+  ;; CHECK:      (func $test (type $ref|$array-i8|_ref|$array-funcref|_=>_none) (param $array-i8 (ref $array-i8)) (param $array-funcref (ref $array-funcref))
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (array.new_data $array-i8 0
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:    (i32.const 5)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (array.new_elem $array-funcref 0
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:    (i32.const 1)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (array.get_u $array-i8
+  ;; CHECK-NEXT:    (local.get $array-i8)
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT:  (drop
+  ;; CHECK-NEXT:   (array.get $array-funcref
+  ;; CHECK-NEXT:    (local.get $array-funcref)
+  ;; CHECK-NEXT:    (i32.const 0)
+  ;; CHECK-NEXT:   )
+  ;; CHECK-NEXT:  )
+  ;; CHECK-NEXT: )
+  (func $test (export "test") (param $array-i8 (ref $array-i8)) (param $array-funcref (ref $array-funcref))
+    (drop
+      (array.new_data $array-i8 0
+        (i32.const 0)
+        (i32.const 5)
+      )
+    )
+    (drop
+      (array.new_elem $array-funcref 0
+        (i32.const 0)
+        (i32.const 1)
+      )
+    )
+    (drop
+      (array.get $array-i8
+        (local.get $array-i8)
+        (i32.const 0)
+      )
+    )
+    (drop
+      (array.get $array-funcref
+        (local.get $array-funcref)
+        (i32.const 0)
+      )
+    )
+  )
+)