Merged Whippet into libguile/whippet

libguile/whippet/src/gc-trace.h

@@ -0,0 +1,56 @@
+#ifndef GC_TRACE_H
+#define GC_TRACE_H
+
+#ifndef GC_IMPL
+#error internal header file, not part of API
+#endif
+
+#include "gc-config.h"
+#include "gc-assert.h"
+#include "gc-conservative-ref.h"
+#include "gc-embedder-api.h"
+
+static inline int gc_has_mutator_conservative_roots(void) {
+  return GC_CONSERVATIVE_ROOTS;
+}
+static inline int gc_mutator_conservative_roots_may_be_interior(void) {
+  return 1;
+}
+static inline int gc_has_global_conservative_roots(void) {
+  return GC_CONSERVATIVE_ROOTS;
+}
+static inline int gc_has_conservative_intraheap_edges(void) {
+  return GC_CONSERVATIVE_TRACE;
+}
+
+static inline int gc_has_conservative_roots(void) {
+  return gc_has_mutator_conservative_roots() ||
+    gc_has_global_conservative_roots();
+}
+
+enum gc_trace_kind {
+  GC_TRACE_PRECISELY,
+  GC_TRACE_NONE,
+  GC_TRACE_CONSERVATIVELY,
+  GC_TRACE_EPHEMERON,
+};
+
+struct gc_trace_plan {
+  enum gc_trace_kind kind;
+  size_t size; // For conservative tracing.
+};
+
+static inline int
+gc_conservative_ref_might_be_a_heap_object(struct gc_conservative_ref ref,
+                                           int possibly_interior) {
+  // Assume that the minimum page size is 4096, and that the first page
+  // will contain no heap objects.
+  if (gc_conservative_ref_value(ref) < 4096)
+    return 0;
+  if (possibly_interior)
+    return 1;
+  return gc_is_valid_conservative_ref_displacement
+    (gc_conservative_ref_value(ref) & (sizeof(uintptr_t) - 1));
+}
+
+#endif // GC_TRACE_H