Update GC code for latest fork (envoyproxy#115)

internal/gc/gc_conservative.go

@@ -13,13 +13,31 @@ import (
 void* GC_malloc(unsigned int size);
 void GC_free(void* ptr);
 void GC_gcollect();
+
+void onCollectionEvent();
 */
 import "C"
 
-// Initialize the memory allocator. We currently do not have anything needing initialization.
+//export GC_set_on_collection_event
+func GC_set_on_collection_event(f unsafe.Pointer)
+
+const (
+	gcEventStart = 0
+)
+
+//export onCollectionEvent
+func onCollectionEvent(eventType uint32) {
+	switch eventType {
+	case gcEventStart:
+		markStack()
+	}
+}
+
+// Initialize the memory allocator.
 //
 //go:linkname initHeap runtime.initHeap
 func initHeap() {
+	GC_set_on_collection_event(C.onCollectionEvent)
 }
 
 // alloc tries to find some free space on the heap, possibly doing a garbage
@@ -40,22 +58,17 @@ func free(ptr unsafe.Pointer) {
 	C.GC_free(ptr)
 }
 
+//go:linkname markRoots runtime.markRoots
+func markRoots(start, end uintptr) {
+	// Roots are already registered in bdwgc so we have nothing to do here.
+}
+
+//go:linkname markStack runtime.markStack
+func markStack()
+
 // GC performs a garbage collection cycle.
 //
 //go:linkname GC runtime.GC
 func GC() {
 	C.GC_gcollect()
 }
-
-//go:linkname KeepAlive runtime.KeepAlive
-func KeepAlive(x interface{}) {
-	// no-op should be fine, pointers are tracked in a shadow stack which will keep references
-	// to pointers throughout a function call regardless of calling this.
-	// TODO(anuraaga): Verify this
-}
-
-//go:linkname SetFinalizer runtime.SetFinalizer
-func SetFinalizer(obj interface{}, finalizer interface{}) {
-	// Unimplemented for now.
-	// TODO(anuraaga): Try using GC_register_finalizer to implement
-}

magefiles/magefile.go

@@ -193,7 +193,7 @@ func Build() error {
 	script := fmt.Sprintf(`
 cd /src && \
 tinygo build -gc=custom -opt=2 -o %s -scheduler=none -target=wasi %s`, filepath.Join("build", "mainraw.wasm"), buildTagArg)
-	if err := sh.RunV("docker", "run", "--pull=always", "--rm", "-v", fmt.Sprintf("%s:/src", wd), "ghcr.io/corazawaf/coraza-proxy-wasm/buildtools-tinygo:sha-447795c",
+	if err := sh.RunV("docker", "run", "--pull=always", "--rm", "-v", fmt.Sprintf("%s:/src", wd), "ghcr.io/corazawaf/coraza-proxy-wasm/buildtools-tinygo:sha-63723e9",
 		"bash", "-c", script); err != nil {
 		return err
 	}