use stack-based set to prevent infinite recursion rather than a static one

src/Val.cc

@@ -1322,12 +1322,12 @@ ValPtr ListVal::DoClone(CloneState* state)
 	return lv;
 	}
 
-unsigned int ListVal::Footprint() const
+unsigned int ListVal::Footprint(std::set<const RecordVal*>* analyzed_records) const
 	{
 	unsigned int fp = vals.size();
 
 	for ( const auto& val : vals )
-		fp += val->Footprint();
+		fp += val->Footprint(analyzed_records);
 
 	return fp;
 	}
@@ -2683,7 +2683,7 @@ ValPtr TableVal::DoClone(CloneState* state)
 	return tv;
 	}
 
-unsigned int TableVal::Footprint() const
+unsigned int TableVal::Footprint(std::set<const RecordVal*>* analyzed_records) const
 	{
 	unsigned int fp = table_val->Length();
 
@@ -2693,9 +2693,9 @@ unsigned int TableVal::Footprint() const
 		auto vl = table_hash->RecoverVals(*k);
 		auto v = iter.GetValue<TableEntryVal*>()->GetVal();
 
-		fp += vl->Footprint();
+		fp += vl->Footprint(analyzed_records);
 		if ( v )
-			fp += v->Footprint();
+			fp += v->Footprint(analyzed_records);
 		}
 
 	return fp;
@@ -3066,18 +3066,13 @@ ValPtr RecordVal::DoClone(CloneState* state)
 	return rv;
 	}
 
-unsigned int RecordVal::Footprint() const
+unsigned int RecordVal::Footprint(std::set<const RecordVal*>* analyzed_records) const
 	{
-	// Which records we're in the process of analyzing - used to
+	if ( analyzed_records->count(this) > 0 )
-	// avoid infinite recursion for circular types (which can only
-	// occur due to the presence of records).
-	static std::unordered_set<const RecordVal*> pending_records;
-
-	if ( pending_records.count(this) > 0 )
 		// Footprint is 1 for the RecordVal itself.
 		return 1;
 
-	pending_records.insert(this);
+	analyzed_records->insert(this);
 
 	int n = NumFields();
 	unsigned int fp = n;
@@ -3089,10 +3084,10 @@ unsigned int RecordVal::Footprint() const
 
 		auto f_i = GetField(i);
 		if ( f_i )
-			fp += f_i->Footprint();
+			fp += f_i->Footprint(analyzed_records);
 		}
 
-	pending_records.erase(this);
+	analyzed_records->erase(this);
 
 	return fp;
 	}
@@ -3620,7 +3615,7 @@ bool VectorVal::Concretize(const TypePtr& t)
 	return true;
 	}
 
-unsigned int VectorVal::Footprint() const
+unsigned int VectorVal::Footprint(std::set<const RecordVal*>* analyzed_records) const
 	{
 	auto n = vector_val->size();
 	unsigned int fp = n;
@@ -3629,7 +3624,7 @@ unsigned int VectorVal::Footprint() const
 		{
 		auto v = At(i);
 		if ( v )
-			fp += v->Footprint();
+			fp += v->Footprint(analyzed_records);
 		}
 
 	return fp;

src/Val.h

@@ -127,9 +127,13 @@ public:
 	 * The number is not meant to be precise, but rather comparable:
 	 * larger footprint correlates with more memory consumption.
 	 *
+	 * @param analyzed_records  A pointer to a set used to track which
+	 * records have been analyzed to date, used to prevent infinite
+	 * recursion.  The set should be empty (but not nil) on the first call.
+	 *
 	 * @return  The total footprint.
 	 */
-	virtual unsigned int Footprint() const { return 1; }
+	virtual unsigned int Footprint(std::set<const RecordVal*>* analyzed_records) const { return 1; }
 
 	// Bytes in total value object.
 	[[deprecated("Remove in v5.1. MemoryAllocation() is deprecated and will be removed. See "
@@ -676,7 +680,7 @@ public:
 
 	void Describe(ODesc* d) const override;
 
-	unsigned int Footprint() const override;
+	unsigned int Footprint(std::set<const RecordVal*>* analyzed_records) const override;
 
 	[[deprecated("Remove in v5.1. MemoryAllocation() is deprecated and will be removed. See "
 	             "GHI-572.")]] unsigned int
@@ -953,7 +957,7 @@ public:
 	// the function in the frame allowing it to capture its closure.
 	void InitDefaultFunc(detail::Frame* f);
 
-	unsigned int Footprint() const override;
+	unsigned int Footprint(std::set<const RecordVal*>* analyzed_records) const override;
 
 	[[deprecated("Remove in v5.1. MemoryAllocation() is deprecated and will be removed. See "
 	             "GHI-572.")]] unsigned int
@@ -1381,7 +1385,7 @@ public:
 		}
 	RecordValPtr CoerceTo(RecordTypePtr other, bool allow_orphaning = false);
 
-	unsigned int Footprint() const override;
+	unsigned int Footprint(std::set<const RecordVal*>* analyzed_records) const override;
 
 	[[deprecated("Remove in v5.1. MemoryAllocation() is deprecated and will be removed. See "
 	             "GHI-572.")]] unsigned int
@@ -1640,7 +1644,7 @@ public:
 	const auto& RawYieldType() const { return yield_type; }
 	const auto& RawYieldTypes() const { return yield_types; }
 
-	unsigned int Footprint() const override;
+	unsigned int Footprint(std::set<const RecordVal*>* analyzed_records) const override;
 
 protected:
 	/**

src/zeek.bif

@@ -2008,7 +2008,8 @@ function global_container_footprints%(%): var_sizes
 			continue;
 
 		auto id_name = zeek::make_intrusive<zeek::StringVal>(id->Name());
-		auto fp = zeek::val_mgr->Count(v->Footprint());
+		std::set<const RecordVal*> analyzed_records;
+		auto fp = zeek::val_mgr->Count(v->Footprint(&analyzed_records));
 		sizes->Assign(std::move(id_name), std::move(fp));
 		}
 
@@ -2024,7 +2025,8 @@ function global_container_footprints%(%): var_sizes
 ## .. zeek:see:: global_container_footprints
 function val_footprint%(v: any%): count
 	%{
-	return zeek::val_mgr->Count(v->Footprint());
+	std::set<const RecordVal*> analyzed_records;
+	return zeek::val_mgr->Count(v->Footprint(&analyzed_records));
 	%}
 
 ## Generates a table with information about all global identifiers. The table