src: show context objects within findrefs

When using `findrefs` we should be able to get all references for the given value, this includes `Context` objects. Refs: #195 PR-URL: #227 Reviewed-By: Matheus Marchini <[email protected]> Reviewed-By: Joyee Cheung <[email protected]>
nodejs · Sep 25, 2018 · 089dcc9 · 089dcc9
1 parent 816c46c
commit 089dcc9
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Showing 7 changed files with 210 additions and 38 deletions.
diff --git a/src/llscan.cc b/src/llscan.cc
@@ -612,6 +612,10 @@ void FindReferencesCmd::PrintReferences(SBCommandReturnObject& result,
       //    "\n", type, addr);
     }
   }
+
+  // Print references found directly inside Context objects
+  Error err;
+  scanner->PrintContextRefs(result, err);
 }
 
 
@@ -668,6 +672,39 @@ char** FindReferencesCmd::ParseScanOptions(char** cmd, ScanType* type) {
   return &cmd[optind - 1];
 }
 
+// Walk all contexts previously stored and print search_value_
+// reference if it exists. Not all values are associated with
+// a context object. It seems that Function-Local variables are
+// stored in the stack, and when some nested closure references
+// it is allocated in a Context object.
+void FindReferencesCmd::ReferenceScanner::PrintContextRefs(
+    SBCommandReturnObject& result, Error& err) {
+  ContextVector* contexts = llscan_->GetContexts();
+  v8::LLV8* v8 = llscan_->v8();
+
+  for (auto ctx : *contexts) {
+    Error err;
+    v8::HeapObject context_obj(v8, ctx);
+    v8::Context c(context_obj);
+
+    v8::Context::Locals locals(&c, err);
+    if (err.Fail()) return;
+
+    for (v8::Context::Locals::Iterator it = locals.begin(); it != locals.end();
+         it++) {
+      if ((*it).raw() == search_value_.raw()) {
+        v8::String _name = it.LocalName(err);
+        if (err.Fail()) return;
+
+        std::string name = _name.ToString(err);
+        if (err.Fail()) return;
+
+        result.Printf("0x%" PRIx64 ": Context.%s=0x%" PRIx64 "\n", c.raw(),
+                      name.c_str(), search_value_.raw());
+      }
+    }
+  }
+}
 
 void FindReferencesCmd::ReferenceScanner::PrintRefs(
     SBCommandReturnObject& result, v8::JSObject& js_obj, Error& err) {
@@ -1193,6 +1230,20 @@ uint64_t FindJSObjectsVisitor::Visit(uint64_t location, uint64_t word) {
   v8::HeapObject heap_object(v8_value);
   if (!heap_object.Check()) return address_byte_size_;
 
+  bool is_context = v8::Context::IsContext(llscan_->v8(), heap_object, err);
+  if (err.Fail()) {
+    return address_byte_size_;
+  }
+
+  if (is_context) {
+    ContextVector* contexts;
+    contexts = llscan_->GetContexts();
+
+    if (std::find(contexts->begin(), contexts->end(), word) == contexts->end())
+      contexts->push_back(word);
+    return address_byte_size_;
+  }
+
   v8::HeapObject map_object = heap_object.GetMap(err);
   if (err.Fail() || !map_object.Check()) return address_byte_size_;
 

diff --git a/src/llscan.h b/src/llscan.h
@@ -13,6 +13,7 @@ namespace llnode {
 class LLScan;
 
 typedef std::vector<uint64_t> ReferencesVector;
+typedef std::vector<uint64_t> ContextVector;
 
 typedef std::map<uint64_t, ReferencesVector*> ReferencesByValueMap;
 typedef std::map<std::string, ReferencesVector*> ReferencesByPropertyMap;
@@ -89,6 +90,9 @@ class FindReferencesCmd : public CommandBase {
     virtual void PrintRefs(lldb::SBCommandReturnObject& result, v8::String& str,
                            Error& err) {}
 
+    virtual void PrintContextRefs(lldb::SBCommandReturnObject& result,
+                                  Error& err) {}
+
     static const char* const property_reference_template;
     static const char* const array_reference_template;
   };
@@ -115,6 +119,9 @@ class FindReferencesCmd : public CommandBase {
     void PrintRefs(lldb::SBCommandReturnObject& result, v8::String& str,
                    Error& err) override;
 
+    void PrintContextRefs(lldb::SBCommandReturnObject& result,
+                          Error& err) override;
+
    private:
     LLScan* llscan_;
     v8::Value search_value_;
@@ -315,6 +322,7 @@ class LLScan {
     return references_by_value_[address];
   };
 
+  // References By Property
   inline bool AreReferencesByPropertyLoaded() {
     return references_by_property_.size() > 0;
   };
@@ -325,6 +333,7 @@ class LLScan {
     return references_by_property_[property];
   };
 
+  // References By String
   inline bool AreReferencesByStringLoaded() {
     return references_by_string_.size() > 0;
   };
@@ -335,6 +344,10 @@ class LLScan {
     return references_by_string_[string_value];
   };
 
+  // Contexts
+  inline bool AreContextsLoaded() { return contexts_.size() > 0; };
+  inline ContextVector* GetContexts() { return &contexts_; }
+
   v8::LLV8* llv8_;
 
  private:
@@ -362,6 +375,7 @@ class LLScan {
   ReferencesByValueMap references_by_value_;
   ReferencesByPropertyMap references_by_property_;
   ReferencesByStringMap references_by_string_;
+  ContextVector contexts_;
 };
 
 }  // namespace llnode

diff --git a/src/llv8-inl.h b/src/llv8-inl.h
@@ -167,6 +167,15 @@ inline bool Map::IsJSObjectMap(Error& err) {
   return InstanceType(err) >= v8()->types()->kFirstJSObjectType;
 }
 
+inline bool Context::IsContext(LLV8* v8, HeapObject heap_object, Error& err) {
+  if (!heap_object.Check()) return false;
+
+  int64_t type = heap_object.GetType(err);
+  if (err.Fail()) return false;
+
+  return type >= v8->types()->kFirstContextType &&
+         type <= v8->types()->kLastContextType;
+}
 
 inline int64_t Map::InObjectProperties(Error& err) {
   if (!IsJSObjectMap(err)) {
@@ -261,7 +270,6 @@ ACCESSOR(SharedFunctionInfo, scope_info, shared_info()->kScopeInfoOffset,
 ACCESSOR(SharedFunctionInfo, name_or_scope_info,
          shared_info()->kNameOrScopeInfoOffset, HeapObject)
 
-
 HeapObject SharedFunctionInfo::GetScopeInfo(Error& err) {
   if (v8()->shared_info()->kNameOrScopeInfoOffset == -1) return scope_info(err);
 
@@ -580,6 +588,19 @@ inline T Context::GetEmbedderData(int64_t index, Error& err) {
   return embedder_data.Get<T>(index, err);
 }
 
+HeapObject Context::GetScopeInfo(Error& err) {
+  if (v8()->context()->kScopeInfoIndex != -1) {
+    return FixedArray::Get<HeapObject>(v8()->context()->kScopeInfoIndex, err);
+  }
+  JSFunction closure = Closure(err);
+  if (err.Fail()) return HeapObject();
+
+  SharedFunctionInfo info = closure.Info(err);
+  if (err.Fail()) return HeapObject();
+
+  return info.GetScopeInfo(err);
+}
+
 inline Value Context::ContextSlot(int index, Error& err) {
   return FixedArray::Get<Value>(v8()->context()->kMinContextSlots + index, err);
 }

diff --git a/src/llv8.cc b/src/llv8.cc
@@ -876,6 +876,10 @@ std::string HeapObject::GetTypeName(Error& err) {
   if (type == v8()->types()->kMapType) {
     return "(Map)";
   }
+  if (type >= v8()->types()->kFirstContextType &&
+      type <= v8()->types()->kLastContextType) {
+    return "Context";
+  }
 
   if (JSObject::IsObjectType(v8(), type)) {
     v8::HeapObject map_obj = GetMap(err);
@@ -1058,17 +1062,43 @@ std::string FixedArray::InspectContents(int length, Error& err) {
   return res;
 }
 
-HeapObject Context::GetScopeInfo(Error& err) {
-  if (v8()->context()->kScopeInfoIndex != -1) {
-    return FixedArray::Get<HeapObject>(v8()->context()->kScopeInfoIndex, err);
-  }
-  JSFunction closure = Closure(err);
-  if (err.Fail()) return HeapObject();
+// Context locals iterator implementations
+Context::Locals::Locals(Context* context, Error& err) {
+  context_ = context;
+  HeapObject scope_obj = context_->GetScopeInfo(err);
+  if (err.Fail()) return;
+
+  scope_info_ = ScopeInfo(scope_obj);
+  Smi param_count_smi = scope_info_.ParameterCount(err);
+  if (err.Fail()) return;
+  Smi stack_count_smi = scope_info_.StackLocalCount(err);
+  if (err.Fail()) return;
+  Smi local_count_smi = scope_info_.ContextLocalCount(err);
+  if (err.Fail()) return;
+
+  param_count_ = param_count_smi.GetValue();
+  stack_count_ = stack_count_smi.GetValue();
+  local_count_ = local_count_smi.GetValue();
+}
 
-  SharedFunctionInfo info = closure.Info(err);
-  if (err.Fail()) return HeapObject();
+Context::Locals::Iterator Context::Locals::begin() { return Iterator(0, this); }
 
-  return info.GetScopeInfo(err);
+Context::Locals::Iterator Context::Locals::end() {
+  return Iterator(local_count_, this);
+}
+
+const Context::Locals::Iterator Context::Locals::Iterator::operator++(int) {
+  current_++;
+  return Iterator(current_, this->outer_);
+}
+
+bool Context::Locals::Iterator::operator!=(Context::Locals::Iterator that) {
+  return current_ != that.current_ || outer_->context_ != that.outer_->context_;
+}
+
+v8::Value Context::Locals::Iterator::operator*() {
+  Error err;
+  return outer_->context_->ContextSlot(current_, err);
 }
 
 std::string Context::Inspect(InspectOptions* options, Error& err) {
@@ -1093,13 +1123,6 @@ std::string Context::Inspect(InspectOptions* options, Error& err) {
 
   ScopeInfo scope(scope_obj);
 
-  Smi param_count_smi = scope.ParameterCount(err);
-  if (err.Fail()) return std::string();
-  Smi stack_count_smi = scope.StackLocalCount(err);
-  if (err.Fail()) return std::string();
-  Smi local_count_smi = scope.ContextLocalCount(err);
-  if (err.Fail()) return std::string();
-
   HeapObject heap_previous = HeapObject(previous);
   if (heap_previous.Check()) {
     char tmp[128];
@@ -1145,19 +1168,19 @@ std::string Context::Inspect(InspectOptions* options, Error& err) {
     res += ">";
   }
 
-  int param_count = param_count_smi.GetValue();
-  int stack_count = stack_count_smi.GetValue();
-  int local_count = local_count_smi.GetValue();
-  for (int i = 0; i < local_count; i++) {
-    String name = scope.ContextLocalName(i, param_count, stack_count, err);
+  Context::Locals locals(this, err);
+  if (err.Fail()) return std::string();
+  for (v8::Context::Locals::Iterator it = locals.begin(); it != locals.end();
+       it++) {
+    String name = it.LocalName(err);
     if (err.Fail()) return std::string();
 
     if (!res.empty()) res += ",\n";
 
     res += options->get_indent_spaces() + name.ToString(err) + "=";
     if (err.Fail()) return std::string();
 
-    Value value = ContextSlot(i, err);
+    Value value = it.GetValue(err);
     if (err.Fail()) return std::string();
 
     InspectOptions val_options;

diff --git a/src/llv8.h b/src/llv8.h
@@ -384,6 +384,19 @@ class NameDictionary : public FixedArray {
   inline int64_t Length(Error& err);
 };
 
+class ScopeInfo : public FixedArray {
+ public:
+  V8_VALUE_DEFAULT_METHODS(ScopeInfo, FixedArray)
+
+  inline Smi ParameterCount(Error& err);
+  inline Smi StackLocalCount(Error& err);
+  inline Smi ContextLocalCount(Error& err);
+
+  inline String ContextLocalName(int index, int param_count, int stack_count,
+                                 Error& err);
+  inline HeapObject MaybeFunctionName(Error& err);
+};
+
 class Context : public FixedArray {
  public:
   V8_VALUE_DEFAULT_METHODS(Context, FixedArray)
@@ -397,23 +410,51 @@ class Context : public FixedArray {
   inline Value ContextSlot(int index, Error& err);
 
   std::string Inspect(InspectOptions* options, Error& err);
+  static inline bool IsContext(LLV8* v8, HeapObject heap_object, Error& err);
+
+  // Iterator class to walk all local references on a context
+  class Locals {
+   public:
+    class Iterator {
+     public:
+      Value operator*();
+      const Context::Locals::Iterator operator++(int);
+      bool operator!=(Context::Locals::Iterator that);
+
+      inline Iterator(int current, Locals* outer)
+          : current_(current), outer_(outer){};
+
+      String LocalName(Error& err) {
+        return outer_->scope_info_.ContextLocalName(
+            current_, outer_->param_count_, outer_->stack_count_, err);
+      }
+
+      Value GetValue(Error& err) {
+        return outer_->context_->ContextSlot(current_, err);
+      }
+
+     private:
+      int current_;
+      Locals* outer_;
+    };
+
+    Locals(Context* context, Error& err);
+
+    Iterator begin();
+    Iterator end();
+
+   private:
+    int local_count_;
+    int param_count_;
+    int stack_count_;
+    Context* context_;
+    ScopeInfo scope_info_;
+  };
 
  private:
   inline JSFunction Closure(Error& err);
 };
 
-class ScopeInfo : public FixedArray {
- public:
-  V8_VALUE_DEFAULT_METHODS(ScopeInfo, FixedArray)
-
-  inline Smi ParameterCount(Error& err);
-  inline Smi StackLocalCount(Error& err);
-  inline Smi ContextLocalCount(Error& err);
-
-  inline String ContextLocalName(int index, int param_count, int stack_count,
-                                 Error& err);
-  inline HeapObject MaybeFunctionName(Error& err);
-};
 
 class Oddball : public HeapObject {
  public:

diff --git a/test/common.js b/test/common.js
@@ -33,7 +33,9 @@ else
 exports.llnodePath = path.join(exports.projectDir, pluginName);
 exports.saveCoreTimeout = 360 * 1000;
 exports.loadCoreTimeout = 60 * 1000;
-exports.versionMark = /^lldb-|^lldb version/;
+
+let versionMark = /^lldb-|^lldb version/;
+exports.versionMark = versionMark;
 
 function SessionOutput(session, stream, timeout) {
   EventEmitter.call(this);
@@ -316,6 +318,20 @@ Session.prototype.send = function send(line, callback) {
   this.lldb.stdin.write(line + '\n', callback);
 };
 
+Session.prototype.hasSymbol = function hasSymbol(symbol, callback) {
+  this.send('target modules dump symtab');
+  this.send('version');
+
+  let pattern = new RegExp(symbol);
+  this.linesUntil(versionMark, (err, lines) => {
+    if(pattern.test(lines.join('\n'))) {
+      callback(err, true);
+    } else {
+      return callback(err, false);
+    }
+  });
+}
+
 exports.generateRanges = function generateRanges(core, dest, cb) {
   let script;
   if (process.platform === 'darwin')