WIP fix(gnovm): patch edge condition in garbage collector

gnovm/pkg/gnolang/garbage_collector.go

@@ -122,15 +122,11 @@ func GCVisitorFn(gcCycle int64, alloc *Allocator, visitCount int64) Visitor {
 		}
 
 		if oo, isObject := v.(Object); isObject {
-			defer func() {
-				// Finally bump cycle for object.
-				oo.SetLastGCCycle(gcCycle)
-			}()
-
 			// Return if already measured.
 			if debug {
 				debug.Printf("oo.GetLastGCCycle: %d, gcCycle: %d\n", oo.GetLastGCCycle(), gcCycle)
 			}
+
 			if oo.GetLastGCCycle() == gcCycle {
 				return false // but don't stop
 			}
@@ -140,17 +136,24 @@ func GCVisitorFn(gcCycle int64, alloc *Allocator, visitCount int64) Visitor {
 
 		// Add object size to alloc.
 		size := v.GetShallowSize()
-		alloc.Allocate(size)
 
-		// Stop if alloc max exceeded.
+		// Stop if alloc max exceeded during GC.
 		// NOTE: Unlikely to occur, but keep it here for
 		// now to handle potential edge cases.
 		// Consider removing it later if no issues arise.
 		maxBytes, curBytes := alloc.Status()
-		if maxBytes < curBytes {
+		if maxBytes < curBytes+size {
 			return true
 		}
 
+		alloc.Allocate(size)
+
+		// bump before visiting associated,
+		// this avoids infinite recurse.
+		if oo, isObject := v.(Object); isObject {
+			oo.SetLastGCCycle(gcCycle)
+		}
+
 		// Invoke the traverser on v.
 		stop := v.VisitAssociated(vis)
 
@@ -198,8 +201,18 @@ func (fv *FuncValue) VisitAssociated(vis Visitor) (stop bool) {
 		}
 	}
 
-	// Skip visiting the parent to avoid redundancy
-	// and prevent a potential cycle.
+	// Visit parent.
+	switch v := fv.Parent.(type) {
+	case nil:
+		return
+	case *Block:
+		if v != nil {
+			stop = vis(v)
+		}
+	case RefValue:
+		stop = vis(v)
+	}
+
 	return
 }
 

gnovm/tests/files/alloc_0.gno

@@ -16,7 +16,7 @@ func main() {
 }
 
 // Output:
-// MemStats:  Allocator{maxBytes:100000000, bytes:6358}
+// MemStats:  Allocator{maxBytes:100000000, bytes:6454}
 
 // TypeCheckError:
 // main/files/alloc_0.gno:13:2: declared and not used: f1

gnovm/tests/files/alloc_1.gno

@@ -21,7 +21,7 @@ func main() {
 }
 
 // Output:
-// MemStats:  Allocator{maxBytes:100000000, bytes:7608}
+// MemStats:  Allocator{maxBytes:100000000, bytes:7704}
 
 // TypeCheckError:
 // main/files/alloc_1.gno:18:2: declared and not used: S1

gnovm/tests/files/alloc_3.gno

@@ -11,7 +11,7 @@ func main() {
 }
 
 // Output:
-// MemStats after GC:  Allocator{maxBytes:110000000, bytes:5704}
+// MemStats after GC:  Allocator{maxBytes:110000000, bytes:5800}
 
 // TypeCheckError:
 // main/files/alloc_3.gno:7:2: declared and not used: data

gnovm/tests/files/alloc_4.gno

@@ -22,5 +22,5 @@ func main() {
 }
 
 // Output:
-// memstats in main after first GC:  Allocator{maxBytes:50000, bytes:11438}
+// memstats in main after first GC:  Allocator{maxBytes:50000, bytes:11630}
 // memstats in main after second GC:  Allocator{maxBytes:50000, bytes:7069}

gnovm/tests/files/alloc_5.gno

@@ -19,7 +19,7 @@ func main() {
 }
 
 // Output:
-// memstats in main after GC:  Allocator{maxBytes:100000000, bytes:6048}
+// memstats in main after GC:  Allocator{maxBytes:100000000, bytes:6144}
 
 // TypeCheckError:
 // main/files/alloc_5.gno:7:2: declared and not used: data

gnovm/tests/files/alloc_6.gno

@@ -13,7 +13,7 @@ func main() {
 }
 
 // Output:
-// memstats in main after GC:  Allocator{maxBytes:100000000, bytes:6048}
+// memstats in main after GC:  Allocator{maxBytes:100000000, bytes:6144}
 
 // TypeCheckError:
 // main/files/alloc_6.gno:7:6: declared and not used: a

gnovm/tests/files/alloc_6a.gno

@@ -15,7 +15,7 @@ func main() {
 }
 
 // Output:
-// memstats in main after GC:  Allocator{maxBytes:100000000, bytes:6554}
+// memstats in main after GC:  Allocator{maxBytes:100000000, bytes:6650}
 
 // TypeCheckError:
 // main/files/alloc_6a.gno:8:7: declared and not used: a

gnovm/tests/files/alloc_7.gno

@@ -13,7 +13,7 @@ func main() {
 }
 
 // Output:
-// MemStats:  Allocator{maxBytes:100000000, bytes:5888}
+// MemStats:  Allocator{maxBytes:100000000, bytes:5984}
 
 // TypeCheckError:
 // main/files/alloc_7.gno:10:2: declared and not used: s1

gnovm/tests/files/alloc_8.gno

@@ -0,0 +1,12 @@
+// MAXALLOC: 50000000
+package main
+
+func recurse(n int) {
+	recurse(n + 1)
+}
+func main() {
+	recurse(0)
+}
+
+// Error:
+// should not happen, allocation limit exceeded while gc.