RemoveUnusedModuleElements: Referenced elems refer to their offsets (#8750)

Author: kripken

src/passes/RemoveUnusedModuleElements.cpp

@@ -764,6 +764,9 @@ struct Analyzer {
     } else if (kind == ModuleElementKind::ElementSegment) {
       // TODO: We could empty out parts of the segment we don't need.
       auto* segment = module->getElementSegment(value);
+      if (segment->offset) {
+        addReferences(segment->offset);
+      }
       for (auto* item : segment->data) {
         addReferences(item);
       }

test/lit/passes/remove-unused-module-elements_tnh.wast

@@ -236,3 +236,45 @@
  ;; T_N_H:      (export "mem" (memory $mem))
  (export "mem" (memory $mem))
 )
+
+;; The exported function has a call_indirect, which refers to the table and
+;; elem. The elem refers to the global, so it must not be removed (in either TNH
+;; or not).
+(module
+ ;; CHECK:      (type $nop (func))
+ ;; T_N_H:      (type $nop (func))
+ (type $nop (func))
+
+ ;; CHECK:      (global $g i32 (i32.const 0))
+ ;; T_N_H:      (global $g i32 (i32.const 0))
+ (global $g i32 (i32.const 0))
+
+ ;; CHECK:      (table $table 50 50 funcref)
+ ;; T_N_H:      (table $table 50 50 funcref)
+ (table $table 50 50 funcref)
+
+ ;; CHECK:      (elem $elem (global.get $g) $func)
+ ;; T_N_H:      (elem $elem (global.get $g) $func)
+ (elem $elem (global.get $g) $func)
+
+ ;; CHECK:      (export "func" (func $func))
+
+ ;; CHECK:      (func $func (type $nop)
+ ;; CHECK-NEXT:  (call_indirect $table (type $nop)
+ ;; CHECK-NEXT:   (i32.const 0)
+ ;; CHECK-NEXT:  )
+ ;; CHECK-NEXT: )
+ ;; T_N_H:      (export "func" (func $func))
+
+ ;; T_N_H:      (func $func (type $nop)
+ ;; T_N_H-NEXT:  (call_indirect $table (type $nop)
+ ;; T_N_H-NEXT:   (i32.const 0)
+ ;; T_N_H-NEXT:  )
+ ;; T_N_H-NEXT: )
+ (func $func (export "func") (type $nop)
+  (call_indirect (type $nop)
+   (i32.const 0)
+  )
+ )
+)
+