[csa] add hint to CAST error message to break in mksnapshot

Change-Id: I51a22de5d6367c38056ea91eface4f69f6651993
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1664069Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62274}

src/compiler/code-assembler.cc

@@ -1206,6 +1206,13 @@ void CodeAssembler::HandleException(Node* node) {
   raw_assembler()->AddNode(raw_assembler()->common()->IfSuccess(), node);
 }
 
+std::string CodeAssembler::CSADebugHint() {
+  std::stringstream s;
+  s << "Run mksnapshot with --csa-trap-on-node=" << state()->name() << ","
+    << state()->raw_assembler_->NodeCount() << " to break in CSA code.";
+  return s.str();
+}
+
 namespace {
 template <size_t kMaxSize>
 class NodeArray {

src/compiler/code-assembler.h

@@ -739,7 +739,10 @@ class V8_EXPORT_PRIVATE CodeAssembler {
                            code_assembler_->SmiConstant(
                                static_cast<int>(ObjectTypeOf<A>::value))),
             std::make_pair(MachineType::AnyTagged(),
-                           code_assembler_->StringConstant(location_)));
+                           code_assembler_->StringConstant(
+                               (location_ + std::string("\n") +
+                                code_assembler_->CSADebugHint())
+                                   .c_str())));
       }
 #endif
       return TNode<A>::UncheckedCast(node_);
@@ -1417,6 +1420,8 @@ class V8_EXPORT_PRIVATE CodeAssembler {
   void GotoIfException(Node* node, Label* if_exception,
                        Variable* exception_var = nullptr);
 
+  std::string CSADebugHint();
+
   // Helpers which delegate to RawMachineAssembler.
   Factory* factory() const;
   Isolate* isolate() const;

src/compiler/raw-machine-assembler.cc

@@ -735,6 +735,8 @@ Node* RawMachineAssembler::MakeNode(const Operator* op, int input_count,
   return graph()->NewNodeUnchecked(op, input_count, inputs);
 }
 
+size_t RawMachineAssembler::NodeCount() { return graph_->NodeCount(); }
+
 RawMachineLabel::~RawMachineLabel() {
 #if DEBUG
   if (bound_ == used_) return;

src/compiler/raw-machine-assembler.h

@@ -1067,6 +1067,8 @@ class V8_EXPORT_PRIVATE RawMachineAssembler {
     return AddNode(op, sizeof...(args) + 1, buffer);
   }
 
+  size_t NodeCount();
+
   void SetSourcePosition(const char* file, int line);
   SourcePositionTable* source_positions() { return source_positions_; }
 

test/cctest/heap/test-heap.cc

@@ -6523,8 +6523,9 @@ UNINITIALIZED_TEST(OutOfMemoryLargeObjects) {
     }
   }
   CHECK_LE(state.old_generation_capacity_at_oom, kOldGenerationLimit);
-  CHECK_LE(kOldGenerationLimit, state.old_generation_capacity_at_oom +
-                                    state.new_space_capacity_at_oom +
+  size_t size = std::max(state.old_generation_capacity_at_oom,
+                         state.memory_allocator_size_at_oom);
+  CHECK_LE(kOldGenerationLimit, size + state.new_space_capacity_at_oom +
                                     state.new_lo_space_size_at_oom +
                                     FixedArray::SizeFor(kFixedArrayLength));
   CHECK_LE(