Changeset 2efe4b8 for src/Common/GC.h

Timestamp:

Apr 25, 2018, 3:42:34 PM (5 years ago)

Author:

Aaron Moss <a3moss@…>

Branches:

new-env, with_gc

Children:

1cdfa82

Parents:

5af7306

Message:

Assorted GC bugfixes

File:

• src/Common/GC.h (modified) (4 diffs)

src/Common/GC.h

@@ -16 +16 @@
 #pragma once
 
+#include <cassert>
 #include <vector>
 
 class GC_Object;
 class BaseSyntaxNode;
+class GC_Guard;
 
 /// Manually traced and called garbage collector
 class GC {
         friend class GcTracer;
+        friend class GC_Guard;
+
+        /// Collects the youngest generation, placing survivors in previous generation.
+        /// Young generation objects cannot be kept alive by pointers from older generation.
+        /// Older generation is used for subsequent new objects.
+        void collect_young();
 public:
         /// Gets singleton GC instance
@@ -38 +46 @@
 
         /// Start new generation for subsequent new objects
-        void new_generation();
+        GC_Guard new_generation();
 
         /// Traces all static roots
         void trace_static_roots();
-
-        /// Collects the youngest generation, placing survivors in previous generation.
-        /// Young generation objects cannot be kept alive by pointers from older generation.
-        /// Older generation is used for subsequent new objects.
-        void collect_young();
 
         /// Collects oldest generation; use oldest generation afterward.
@@ -68 +71 @@
 };
 
+/// Cleanup object for young generation
+class GC_Guard {
+        friend class GC;
+
+        GC& gc;      ///< GC associated with
+        unsigned g;  ///< Generation constructed for
+
+        GC_Guard( GC& gc, unsigned g ) : gc(gc), g(g) {}
+
+public:
+        ~GC_Guard() {
+                assert( gc.g == g && "collecting current generation" );
+                gc.collect_young();
+        }
+};
+
 /// Use young generation until next collection
-inline void new_generation() { GC::get().new_generation(); }
+inline GC_Guard new_generation() { return GC::get().new_generation(); }
 
 // /// no-op default trace
@@ -84 +103 @@
 }
 
-/// Traces young-generation roots and does a young collection
+/// Traces roots without collecting
 template<typename... Args>
-inline void collect_young(Args&... roots) {
+inline void trace(Args&... roots) {
         GC& gc = GC::get();
         traceAll(gc, roots...);
         gc.trace_static_roots();
-        gc.collect_young();
 }
 
-/// Traces roots and collects other elements
+/// Traces roots and collects other elements; should not be any young generations live
 template<typename... Args>
 inline void collect(Args&... roots) {