[wasm] Add {wasm::DebugInfo} class for Liftoff inspection

This adds a {wasm::DebugInfo} struct which will hold the
{wasm::DebugSideTable}s for individual Liftoff functions, and will use
them to construct local scope information.

R=jkummerow@chromium.org, bmeurer@chromium.org

Bug: v8:10019
Change-Id: I7869cec5000e9b126c891a242fcccfc53c67662e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1975758
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65563}

src/debug/debug-scope-iterator.cc

@@ -143,9 +143,7 @@ bool DebugWasmScopeIterator::Done() {
 
 void DebugWasmScopeIterator::Advance() {
   DCHECK(!Done());
-  // Local scope information is only available for interpreted frames currently.
-  if (type_ == debug::ScopeIterator::ScopeTypeGlobal &&
-      frame_->is_wasm_interpreter_entry()) {
+  if (type_ == debug::ScopeIterator::ScopeTypeGlobal) {
     type_ = debug::ScopeIterator::ScopeTypeLocal;
   } else {
     // We use ScopeTypeWith type as marker for done.
@@ -167,15 +165,22 @@ v8::Local<v8::Object> DebugWasmScopeIterator::GetObject() {
       return Utils::ToLocal(wasm::GetGlobalScopeObject(instance));
     }
     case debug::ScopeIterator::ScopeTypeLocal: {
-      Handle<WasmDebugInfo> debug_info(
-          WasmInterpreterEntryFrame::cast(frame_)->debug_info(), isolate_);
-      return Utils::ToLocal(WasmDebugInfo::GetLocalScopeObject(
-          debug_info, frame_->fp(), inlined_frame_index_));
+      if (frame_->is_wasm_interpreter_entry()) {
+        Handle<WasmDebugInfo> debug_info(
+            WasmInterpreterEntryFrame::cast(frame_)->debug_info(), isolate_);
+        return Utils::ToLocal(WasmDebugInfo::GetLocalScopeObject(
+            debug_info, frame_->fp(), inlined_frame_index_));
+      }
+      // Compiled code.
+      DCHECK(frame_->is_wasm_compiled());
+      wasm::DebugInfo* debug_info =
+          WasmCompiledFrame::cast(frame_)->native_module()->GetDebugInfo();
+      return Utils::ToLocal(debug_info->GetLocalScopeObject(
+          isolate_, frame_->pc(), frame_->fp()));
     }
     default:
-      return v8::Local<v8::Object>();
+      return {};
   }
-  return v8::Local<v8::Object>();
 }
 
 int DebugWasmScopeIterator::GetScriptId() {

src/execution/frames.cc

@@ -1903,6 +1903,10 @@ WasmInstanceObject WasmCompiledFrame::wasm_instance() const {
   return WasmInstanceObject::cast(instance);
 }
 
+wasm::NativeModule* WasmCompiledFrame::native_module() const {
+  return module_object().native_module();
+}
+
 WasmModuleObject WasmCompiledFrame::module_object() const {
   return wasm_instance().module_object();
 }

src/execution/frames.h

@@ -950,6 +950,7 @@ class WasmCompiledFrame : public StandardFrame {
 
   // Accessors.
   WasmInstanceObject wasm_instance() const;
+  wasm::NativeModule* native_module() const;
   wasm::WasmCode* wasm_code() const;
   uint32_t function_index() const;
   Script script() const override;

src/wasm/wasm-code-manager.cc

@@ -24,6 +24,7 @@
 #include "src/wasm/compilation-environment.h"
 #include "src/wasm/function-compiler.h"
 #include "src/wasm/jump-table-assembler.h"
+#include "src/wasm/wasm-debug.h"
 #include "src/wasm/wasm-import-wrapper-cache.h"
 #include "src/wasm/wasm-module-sourcemap.h"
 #include "src/wasm/wasm-module.h"
@@ -1854,6 +1855,12 @@ size_t NativeModule::GetNumberOfCodeSpacesForTesting() const {
   return code_allocator_.GetNumCodeSpaces();
 }
 
+DebugInfo* NativeModule::GetDebugInfo() {
+  base::MutexGuard guard(&allocation_mutex_);
+  if (!debug_info_) debug_info_ = std::make_unique<DebugInfo>(this);
+  return debug_info_.get();
+}
+
 void WasmCodeManager::FreeNativeModule(Vector<VirtualMemory> owned_code_space,
                                        size_t committed_size) {
   base::MutexGuard lock(&native_modules_mutex_);

src/wasm/wasm-code-manager.h

@@ -35,6 +35,7 @@ class Isolate;
 
 namespace wasm {
 
+class DebugInfo;
 class NativeModule;
 class WasmCodeManager;
 struct WasmCompilationResult;
@@ -566,6 +567,9 @@ class V8_EXPORT_PRIVATE NativeModule final {
   // Retrieve the number of separately reserved code spaces for this module.
   size_t GetNumberOfCodeSpacesForTesting() const;
 
+  // Get or create the debug info for this NativeModule.
+  DebugInfo* GetDebugInfo();
+
  private:
   friend class WasmCode;
   friend class WasmCodeAllocator;
@@ -691,7 +695,15 @@ class V8_EXPORT_PRIVATE NativeModule final {
   // Data (especially jump table) per code space.
   std::vector<CodeSpaceData> code_space_data_;
 
+  // Whether we want all code to be Liftoff for debugging.
   bool tier_down_ = false;
+
+  // Debug information for this module. You only need to hold the allocation
+  // mutex while getting the {DebugInfo} pointer, or initializing this field.
+  // Further accesses to the {DebugInfo} do not need to be protected by the
+  // mutex.
+  std::unique_ptr<DebugInfo> debug_info_;
+
   // End of fields protected by {allocation_mutex_}.
   //////////////////////////////////////////////////////////////////////////////
 

src/wasm/wasm-debug.cc

@@ -494,6 +494,38 @@ Handle<JSObject> GetGlobalScopeObject(Handle<WasmInstanceObject> instance) {
   return global_scope_object;
 }
 
+class DebugInfoImpl {
+ public:
+  explicit DebugInfoImpl(NativeModule* native_module)
+      : native_module_(native_module) {}
+
+  Handle<JSObject> GetLocalScopeObject(Isolate* isolate, Address pc,
+                                       Address fp) {
+    Handle<JSObject> local_scope_object =
+        isolate->factory()->NewJSObjectWithNullProto();
+
+    // TODO(clemensb): Fill this with actual values.
+    USE(native_module_);
+
+    return local_scope_object;
+  }
+
+ private:
+  NativeModule* const native_module_;
+
+  DISALLOW_COPY_AND_ASSIGN(DebugInfoImpl);
+};
+
+DebugInfo::DebugInfo(NativeModule* native_module)
+    : impl_(std::make_unique<DebugInfoImpl>(native_module)) {}
+
+DebugInfo::~DebugInfo() = default;
+
+Handle<JSObject> DebugInfo::GetLocalScopeObject(Isolate* isolate, Address pc,
+                                                Address fp) {
+  return impl_->GetLocalScopeObject(isolate, pc, fp);
+}
+
 }  // namespace wasm
 
 namespace {

src/wasm/wasm-debug.h

@@ -6,8 +6,10 @@
 #define V8_WASM_WASM_DEBUG_H_
 
 #include <algorithm>
+#include <memory>
 #include <vector>
 
+#include "include/v8-internal.h"
 #include "src/base/iterator.h"
 #include "src/base/logging.h"
 #include "src/base/macros.h"
@@ -22,6 +24,9 @@ class WasmInstanceObject;
 
 namespace wasm {
 
+class DebugInfoImpl;
+class NativeModule;
+
 // Side table storing information used to inspect Liftoff frames at runtime.
 // This table is only created on demand for debugging, so it is not optimized
 // for memory size.
@@ -106,6 +111,19 @@ class DebugSideTable {
 // (if the instance has a memory) and the values of all globals.
 Handle<JSObject> GetGlobalScopeObject(Handle<WasmInstanceObject>);
 
+// Debug info per NativeModule, created lazily on demand.
+// Implementation in {wasm-debug.cc} using PIMPL.
+class DebugInfo {
+ public:
+  explicit DebugInfo(NativeModule*);
+  ~DebugInfo();
+
+  Handle<JSObject> GetLocalScopeObject(Isolate*, Address pc, Address fp);
+
+ private:
+  std::unique_ptr<DebugInfoImpl> impl_;
+};
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8

src/wasm/wasm-objects.h

@@ -801,6 +801,8 @@ class WasmJSFunctionData : public Struct {
   OBJECT_CONSTRUCTORS(WasmJSFunctionData, Struct);
 };
 
+// Debug info used for wasm debugging in the interpreter. For Liftoff debugging,
+// all information is held off-heap in {wasm::DebugInfo}.
 class WasmDebugInfo : public Struct {
  public:
   NEVER_READ_ONLY_SPACE

test/inspector/debugger/wasm-scope-info-expected.txt

@@ -25,6 +25,7 @@ at func (2:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -44,6 +45,7 @@ at func (3:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -63,6 +65,7 @@ at func (4:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -82,6 +85,7 @@ at func (5:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -101,6 +105,7 @@ at func (6:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -120,6 +125,7 @@ at func (7:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -139,6 +145,7 @@ at func (8:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -158,6 +165,7 @@ at func (9:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -177,6 +185,7 @@ at func (10:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -196,6 +205,7 @@ at func (11:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -215,6 +225,7 @@ at func (12:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -234,6 +245,7 @@ at func (13:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -253,6 +265,7 @@ at func (14:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -272,6 +285,7 @@ at func (15:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -291,6 +305,7 @@ at func (16:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -310,6 +325,7 @@ at func (17:2):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -329,6 +345,7 @@ at func (18:0):
 at call_func (5:2):
  - scope (global):
    globals: "global#0": 15 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals

test/inspector/debugger/wasm-scope-info-liftoff-expected.txt

@@ -26,9 +26,11 @@ at C (interpreted) (2:2):
 at B (liftoff) (7:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at A (liftoff) (2:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -48,9 +50,11 @@ at C (interpreted) (3:2):
 at B (liftoff) (7:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at A (liftoff) (2:2):
  - scope (global):
    globals: "global#0": 0 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -70,9 +74,11 @@ at C (interpreted) (4:2):
 at B (liftoff) (7:2):
  - scope (global):
    globals: "global#0": 42 (number)
+ - scope (local):
 at A (liftoff) (2:2):
  - scope (global):
    globals: "global#0": 42 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -92,9 +98,11 @@ at C (interpreted) (5:2):
 at B (liftoff) (7:2):
  - scope (global):
    globals: "global#0": 42 (number)
+ - scope (local):
 at A (liftoff) (2:2):
  - scope (global):
    globals: "global#0": 42 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals
@@ -114,9 +122,11 @@ at C (interpreted) (6:0):
 at B (liftoff) (7:2):
  - scope (global):
    globals: "global#0": 42 (number)
+ - scope (local):
 at A (liftoff) (2:2):
  - scope (global):
    globals: "global#0": 42 (number)
+ - scope (local):
 at (anonymous) (0:17):
  - scope (global):
    -- skipped globals