[wasm] Syntactially refactor {PublishCodeLocked}

This is just adding an early exit, to avoid a big if-block spanning the
whole method.
Instead of doing this in the follow-up CL, which adds even more code to
that block, I pulled it out for easier review.

R=thibaudm@chromium.org

Bug: v8:11556
Change-Id: Ie4f2e0635fe9875c90d32be8224f1b0709c82e00
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2757687Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73405}

src/wasm/wasm-code-manager.cc

@@ -1132,16 +1132,22 @@ WasmCode::Kind GetCodeKind(const WasmCompilationResult& result) {
   }
 }
 
-WasmCode* NativeModule::PublishCodeLocked(std::unique_ptr<WasmCode> code) {
+WasmCode* NativeModule::PublishCodeLocked(
+    std::unique_ptr<WasmCode> owned_code) {
   // The caller must hold the {allocation_mutex_}, thus we fail to lock it here.
   DCHECK(!allocation_mutex_.TryLock());
 
+  WasmCode* code = owned_code.get();
+  new_owned_code_.emplace_back(std::move(owned_code));
+
   // Add the code to the surrounding code ref scope, so the returned pointer is
   // guaranteed to be valid.
-  WasmCodeRefScope::AddRef(code.get());
+  WasmCodeRefScope::AddRef(code);
+
+  if (code->IsAnonymous() || code->index() < module_->num_imported_functions) {
+    return code;
+  }
 
-  if (!code->IsAnonymous() &&
-      code->index() >= module_->num_imported_functions) {
   DCHECK_LT(code->index(), num_functions());
 
   code->RegisterTrapHandlerData();
@@ -1171,7 +1177,7 @@ WasmCode* NativeModule::PublishCodeLocked(std::unique_ptr<WasmCode> code) {
             // Tiered up: Install if the tier is higher than before.
             : prior_code->tier() < code->tier()));
   if (update_code_table) {
-      code_table_[slot_idx] = code.get();
+    code_table_[slot_idx] = code;
     if (prior_code) {
       WasmCodeRefScope::AddRef(prior_code);
       // The code is added to the current {WasmCodeRefScope}, hence the ref
@@ -1190,10 +1196,8 @@ WasmCode* NativeModule::PublishCodeLocked(std::unique_ptr<WasmCode> code) {
       code->tier() == ExecutionTier::kTurbofan) {
     liftoff_bailout_count_.fetch_add(1);
   }
-  }
-  WasmCode* result = code.get();
-  new_owned_code_.emplace_back(std::move(code));
-  return result;
+
+  return code;
 }
 
 void NativeModule::ReinstallDebugCode(WasmCode* code) {