[Liftoff] Also disassemble code on the native heap

With --jit-to-native, we current don't disassemble any Liftoff code.
This CL adds that, and also adds printing of relocation info of native
wasm code.

R=mstarzinger@chromium.org
CC=titzer@chromium.org

Bug: v8:6600
Change-Id: Icb1249868224180171107b82e2dd7dc69e23db16
Reviewed-on: https://chromium-review.googlesource.com/863762
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50553}

src/compiler/wasm-compiler.cc

@@ -5218,22 +5218,6 @@ WasmCodeWrapper WasmCompilationUnit::FinishLiftoffCompilation(
         false,                                   // is_turbofanned
         liftoff_.asm_.GetTotalFrameSlotCount(),  // stack_slots
         liftoff_.safepoint_table_offset_);
-#ifdef ENABLE_DISASSEMBLER
-    if (FLAG_print_code || FLAG_print_wasm_code) {
-      // TODO(wasm): Use proper log files, here and elsewhere.
-      OFStream os(stdout);
-      os << "--- Wasm liftoff code ---\n";
-      EmbeddedVector<char, 64> func_name;
-      if (func_name_.start() != nullptr) {
-        SNPrintF(func_name, "#%d:%.*s", func_index(), func_name_.length(),
-                 func_name_.start());
-      } else {
-        SNPrintF(func_name, "wasm#%d", func_index());
-      }
-      code->Disassemble(func_name.start(), os);
-      os << "--- End code ---\n";
-    }
-#endif
     if (isolate_->logger()->is_logging_code_events() ||
         isolate_->is_profiling()) {
       RecordFunctionCompilation(CodeEventListener::FUNCTION_TAG, isolate_, code,
@@ -5241,17 +5225,34 @@ WasmCodeWrapper WasmCompilationUnit::FinishLiftoffCompilation(
     }
 
     PackProtectedInstructions(code);
-    return WasmCodeWrapper(code);
+    ret = WasmCodeWrapper(code);
   } else {
-    // TODO(mtrofin): figure a way to raise events; also, disassembly.
-    // Consider lifting them both to FinishCompilation.
+    // TODO(mtrofin): figure a way to raise events.
+    // Consider lifting it to FinishCompilation.
     native_module_->compiled_module()->source_positions()->set(
         func_index_, *source_positions);
-    return WasmCodeWrapper(
+    ret = WasmCodeWrapper(
         native_module_->AddCode(desc, liftoff_.asm_.GetTotalFrameSlotCount(),
                                 func_index_, liftoff_.safepoint_table_offset_,
                                 std::move(protected_instructions_), true));
   }
+#ifdef ENABLE_DISASSEMBLER
+  if (FLAG_print_code || FLAG_print_wasm_code) {
+    // TODO(wasm): Use proper log files, here and elsewhere.
+    OFStream os(stdout);
+    os << "--- Wasm liftoff code ---\n";
+    EmbeddedVector<char, 64> func_name;
+    if (func_name_.start() != nullptr) {
+      SNPrintF(func_name, "#%d:%.*s", func_index(), func_name_.length(),
+               func_name_.start());
+    } else {
+      SNPrintF(func_name, "wasm#%d", func_index());
+    }
+    ret.Disassemble(func_name.start(), isolate_, os);
+    os << "--- End code ---\n";
+  }
+#endif
+  return ret;
 }
 
 // static

src/wasm/wasm-code-manager.cc

@@ -180,14 +180,20 @@ void WasmCode::ResetTrapHandlerIndex() { trap_handler_index_ = -1; }
 
 void WasmCode::Print(Isolate* isolate) const {
   OFStream os(stdout);
-  if (index_.IsJust()) {
-    os << "index: " << index_.FromJust() << "\n";
-  }
+  Disassemble(nullptr, isolate, os);
+}
+
+void WasmCode::Disassemble(const char* name, Isolate* isolate,
+                           std::ostream& os) const {
+  if (name) os << "name: " << name << "\n";
+  if (index_.IsJust()) os << "index: " << index_.FromJust() << "\n";
   os << "kind: " << GetWasmCodeKindAsString(kind_) << "\n";
   os << "compiler: " << (is_liftoff() ? "Liftoff" : "TurboFan") << "\n";
   size_t body_size = instructions().size();
   os << "Body (size = " << body_size << ")\n";
 
+#ifdef ENABLE_DISASSEMBLER
+
   size_t instruction_size =
       std::min(constant_pool_offset_, safepoint_table_offset_);
   os << "Instructions (size = " << instruction_size << ")\n";
@@ -210,6 +216,14 @@ void WasmCode::Print(Isolate* isolate) const {
     }
     os << "\n";
   }
+
+  os << "RelocInfo (size = " << reloc_size_ << ")\n";
+  for (RelocIterator it(instructions(), reloc_info(), constant_pool());
+       !it.done(); it.next()) {
+    it.rinfo()->Print(isolate, os);
+  }
+  os << "\n";
+#endif  // ENABLE_DISASSEMBLER
 }
 
 const char* GetWasmCodeKindAsString(WasmCode::Kind kind) {

src/wasm/wasm-code-manager.h

@@ -124,6 +124,7 @@ class V8_EXPORT_PRIVATE WasmCode final {
   }
 
   void Print(Isolate* isolate) const;
+  void Disassemble(const char* name, Isolate* isolate, std::ostream& os) const;
 
   ~WasmCode();
 

src/wasm/wasm-code-wrapper.cc

@@ -6,6 +6,7 @@
 
 #include "src/objects.h"
 #include "src/objects/code.h"
+#include "src/wasm/wasm-code-manager.h"
 
 namespace v8 {
 namespace internal {
@@ -34,5 +35,16 @@ const wasm::WasmCode* WasmCodeWrapper::GetWasmCode() const {
 
 bool WasmCodeWrapper::IsCodeObject() const { return !FLAG_wasm_jit_to_native; }
 
+#ifdef ENABLE_DISASSEMBLER
+void WasmCodeWrapper::Disassemble(const char* name, Isolate* isolate,
+                                  std::ostream& os) const {
+  if (IsCodeObject()) {
+    GetCode()->Disassemble(name, os);
+  } else {
+    GetWasmCode()->Disassemble(name, isolate, os);
+  }
+}
+#endif
+
 }  // namespace internal
 }  // namespace v8

src/wasm/wasm-code-wrapper.h

@@ -26,6 +26,10 @@ class WasmCodeWrapper {
   bool is_null() const { return code_ptr_.wasm_code_ == nullptr; }
   bool IsCodeObject() const;
 
+#ifdef ENABLE_DISASSEMBLER
+  void Disassemble(const char* name, Isolate* isolate, std::ostream& os) const;
+#endif
+
  private:
   union {
     const wasm::WasmCode* wasm_code_;