Changeset 24de7b1

Timestamp:

Apr 16, 2018, 3:21:17 PM (7 years ago)

Author:

Aaron Moss <a3moss@…>

Branches:

new-env, with_gc

Children:

fb97252f

Parents:

6f81db3

Message:

Fix more missing visits in GcTracer?, add cycle detection back in, ensure mark isn't broken by defaulted GC_Object copy and assign

Location:

src

Files:

• Common/GC.cc (modified) (2 diffs)
• Common/GC.h (modified) (3 diffs)
• SynTree/GcTracer.h (modified) (3 diffs)

src/Common/GC.cc

@@ -40 +40 @@
 }
 
-const GC& GC::operator<< (const GC_Traceable* obj) const {
+const GC& GC::operator<< (const GC_Object* obj) const {
         if( obj )
         {
@@ -119 +119 @@
 }
 
+GC_Object::GC_Object( const GC_Object& ) {
+        GC::get().register_object( this );
+}
+
+GC_Object::GC_Object( GC_Object&& ) {
+        GC::get().register_object( this );
+}
+
 // Local Variables: //
 // tab-width: 4 //

src/Common/GC.h

@@ -18 +18 @@
 #include <vector>
 
-class GC_Traceable;
 class GC_Object;
 class BaseSyntaxNode;
@@ -30 +29 @@
 
         /// Traces a traceable object
-        const GC& operator<< (const GC_Traceable*) const;
+        const GC& operator<< (const GC_Object*) const;
 
         /// Adds a new object to garbage collection
@@ -111 +110 @@
 }
 
-/// Class that is traced by the GC, but not managed by it
-class GC_Traceable {
+/// Class that is managed by the GC
+class GC_Object {
         friend class GC;
 protected:
         mutable bool mark;
 
+        // Override default constructors to ensure clones are registered and properly marked
+        GC_Object();
+
+        GC_Object(const GC_Object&);
+
+        GC_Object(GC_Object&&);
+
+        GC_Object& operator= (const GC_Object&) { /* do not assign mark */ return *this; }
+
+        GC_Object& operator= (GC_Object&&) { /* do not assign mark */ return *this; }
+
+        // Ensure subclasses can be deleted by garbage collector
+        virtual ~GC_Object() {}
+
         /// override to trace any child objects
         virtual void trace(const GC&) const {}
-};
-
-/// Class that is managed by the GC
-class GC_Object : public GC_Traceable {
-        friend class GC;
-protected:
-        virtual ~GC_Object() {}
-public:
-        GC_Object();
 };
 

src/SynTree/GcTracer.h

@@ -38 +38 @@
         void previsit( BaseSyntaxNode * node ) {
                 // skip tree if already seen
-                // xxx - this should be uncommented (it breaks object cycles), but at the moment it seems 
-                // like the object cycles don't happen and other bugs do
-                // if ( node->mark == gc.mark ) {
-                //      visit_children = false;
-                //      return;
-                // }
+                if ( node->mark == gc.mark ) {
+                        visit_children = false;
+                        return;
+                }
 
                 // mark node
@@ -50 +48 @@
 
         // add visits left out by PassVisitor
+
+        void postvisit( Constant* con ) {
+                maybeAccept( con->get_type(), *visitor );
+        }
 
         void postvisit( Expression* expr ) {
@@ -58 +60 @@
                 postvisit( static_cast<Expression*>(expr) );
                 maybeAccept( expr->function, *visitor );
+        }
+
+        void postvisit( VariableExpr* expr ) {
+                postvisit( static_cast<Expression*>(expr) );
+                maybeAccept( expr->var, *visitor );  // not in PassVisitor because it causes cycle
         }