[wasm] Fix destructor ordering for {NativeModule}.

R=clemensh@chromium.org
BUG=v8:7921

Change-Id: I82a1c5cff7fd00603a509221b448b11d82edee7e
Reviewed-on: https://chromium-review.googlesource.com/1131176Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54356}

src/wasm/wasm-code-manager.cc

@@ -725,6 +725,7 @@ void NativeModule::DisableTrapHandler() {
 
 NativeModule::~NativeModule() {
   TRACE_HEAP("Deleting native module: %p\n", reinterpret_cast<void*>(this));
+  compilation_state_.reset();  // Cancels tasks, needs to be done first.
   wasm_code_manager_->FreeNativeModule(this);
 }
 

src/wasm/wasm-code-manager.h

@@ -387,15 +387,19 @@ class V8_EXPORT_PRIVATE NativeModule final {
   // Jump table used to easily redirect wasm function calls.
   WasmCode* jump_table_ = nullptr;
 
+  // The compilation state keeps track of compilation tasks for this module.
+  // Note that its destructor blocks until all tasks are finished/aborted and
+  // hence needs to be destructed first when this native module dies.
   std::unique_ptr<CompilationState, CompilationStateDeleter> compilation_state_;
 
+  // This mutex protects concurrent calls to {AddCode} and {AddCodeCopy}.
+  mutable base::Mutex allocation_mutex_;
+
   DisjointAllocationPool free_code_space_;
   DisjointAllocationPool allocated_code_space_;
   std::list<VirtualMemory> owned_code_space_;
 
   WasmCodeManager* wasm_code_manager_;
-  // This mutex protects concurrent calls to {AddCode} and {AddCodeCopy}.
-  mutable base::Mutex allocation_mutex_;
   size_t committed_code_space_ = 0;
   int modification_scope_depth_ = 0;
   bool can_request_more_memory_;