Address review: use getGlobal, add test for nested inlining

Author: vouillon

src/tools/wasm-merge.cpp

@@ -590,8 +590,8 @@ void fixTableInitializers() {
   struct Inliner : public PostWalker<Inliner> {
     bool inlined = false;
     void visitGlobalGet(GlobalGet* curr) {
-      auto* global = getModule()->getGlobalOrNull(curr->name);
-      if (global && !global->imported()) {
+      auto* global = getModule()->getGlobal(curr->name);
+      if (!global->imported()) {
         assert(global->init && !global->mutable_);
         replaceCurrent(ExpressionManipulator::copy(global->init, *getModule()));
         inlined = true;

test/lit/merge/table-init-nested.wat

@@ -0,0 +1,29 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: wasm-merge %s first %s.second second -all -S -o - | filecheck %s
+
+;; Like table-init.wat, but the global $g that the table initializer refers to
+;; is fused with a global whose initializer itself refers to another
+;; module-defined global, $a. Inlining $g exposes a reference to $a, which must
+;; be inlined as well, so verify that we keep inlining until the initializer
+;; refers to no module-defined globals.
+
+(module
+  ;; CHECK:      (type $f (func))
+  (type $f (func))
+
+  (global $g (import "second" "g") (ref $f))
+
+  ;; CHECK:      (global $a (ref $f) (ref.func $h))
+
+  ;; CHECK:      (global $g_1 (ref $f) (global.get $a))
+
+  ;; CHECK:      (table $t 3 funcref (ref.func $h))
+  (table $t (export "t") 3 funcref (global.get $g))
+)
+;; CHECK:      (export "t" (table $t))
+
+;; CHECK:      (export "g" (global $g_1))
+
+;; CHECK:      (func $h (type $f)
+;; CHECK-NEXT: )

test/lit/merge/table-init-nested.wat.second

@@ -0,0 +1,9 @@
+(module
+  (type $f (func))
+
+  (func $h)
+
+  (global $a (ref $f) (ref.func $h))
+
+  (global $g (export "g") (ref $f) (global.get $a))
+)