tracking of optimization information associated with statements

src/Stmt.cc

@@ -19,6 +19,7 @@
 #include "zeek/Trigger.h"
 #include "zeek/IntrusivePtr.h"
 #include "zeek/logging/Manager.h"
+#include "zeek/script_opt/StmtOptInfo.h"
 
 #include "zeek/logging/logging.bif.h"
 
@@ -49,11 +50,14 @@ Stmt::Stmt(StmtTag arg_tag)
 	last_access = 0;
 	access_count = 0;
 
+	opt_info = new StmtOptInfo();
+
 	SetLocationInfo(&start_location, &end_location);
 	}
 
 Stmt::~Stmt()
 	{
+	delete opt_info;
 	}
 
 StmtList* Stmt::AsStmtList()

src/StmtBase.h

@@ -48,6 +48,8 @@ class Reducer;
 class Stmt;
 using StmtPtr = IntrusivePtr<Stmt>;
 
+class StmtOptInfo;
+
 class Stmt : public Obj {
 public:
 	StmtTag Tag() const	{ return tag; }
@@ -160,6 +162,10 @@ public:
 			return Obj::GetLocationInfo();
 		}
 
+	// Access script optimization information associated with
+	// this statement.
+	StmtOptInfo* GetOptInfo() const		{ return opt_info; }
+
 protected:
 	explicit Stmt(StmtTag arg_tag);
 
@@ -182,6 +188,10 @@ protected:
 	// derived, if any.  Used as an aid for generating meaningful
 	// and correctly-localized error messages.
 	StmtPtr original = nullptr;
+
+	// Information associated with the Stmt for purposes of
+	// script optimization.
+	StmtOptInfo* opt_info;
 };
 
 } // namespace detail

src/script_opt/StmtOptInfo.h

@@ -0,0 +1,25 @@
+// See the file "COPYING" in the main distribution directory for copyright.
+
+// Auxiliary information associated with statements to aid script
+// optimization.
+
+#pragma once
+
+namespace zeek::detail {
+
+class StmtOptInfo {
+public:
+	// We number statements by their traversal order in the AST.
+	int stmt_num = -1;	// -1 = not assigned yet
+
+	// The confluence block nesting associated with the statement.
+	// We number these using 0 for the outermost block of a function
+	// (which, strictly speaking, isn't a confluence block).
+	int block_level = -1;
+
+	// True if we observe that there is a branch out of the statement
+	// to just beyond its extent, such as due to a "break".
+	bool contains_branch_beyond = false;
+};
+
+} // namespace zeek::detail