wingo pushed a commit to branch wip-whippet
in repository guile.
commit d560676572eb83736ae265ba41213936f7fb9c26
Author: Andy Wingo <wi...@pobox.com>
AuthorDate: Thu May 15 15:15:28 2025 +0200
Wire loader DT_GUILE_GC_ROOT sections to Whippet API
* libguile/loader.c (add_roots):
(scm_trace_loader_conservative_roots):
(process_dynamic_segment): Use Whippet API to register roots.
* libguile/trace.h (struct gc_heap_roots): Define here.
* libguile/whippet-embedder.h (gc_trace_mutator_conservative_roots):
(gc_trace_heap_conservative_roots): Add definitions.
---
libguile/gc.c | 6 ++++++
libguile/loader.c | 42 ++++++++++++++++++++++++++++++++++++++++--
libguile/trace.h | 10 ++++++++++
libguile/whippet-embedder.h | 25 +++++++++++++++++++++++++
4 files changed, 81 insertions(+), 2 deletions(-)
diff --git a/libguile/gc.c b/libguile/gc.c
index 42c93cfc3..289adf3f1 100644
--- a/libguile/gc.c
+++ b/libguile/gc.c
@@ -53,6 +53,7 @@
#include "strings.h"
#include "struct.h"
#include "symbols.h"
+#include "trace.h"
#include "vectors.h"
#include "gc.h"
@@ -634,6 +635,7 @@ scm_gc_unregister_roots (SCM *b, unsigned long n)
+static struct gc_heap_roots heap_roots;
struct gc_mutator *
scm_storage_prehistory (struct gc_stack_addr base)
@@ -661,6 +663,10 @@ scm_storage_prehistory (struct gc_stack_addr base)
abort ();
}
+ // We need to set roots so that scm_trace_loader_conservative_roots
+ // gets called.
+ gc_heap_set_roots(the_gc_heap, &heap_roots);
+
/* Sanity check. */
if (!GC_is_visible (&scm_protects))
abort ();
diff --git a/libguile/loader.c b/libguile/loader.c
index 09bd166ec..bd91601b6 100644
--- a/libguile/loader.c
+++ b/libguile/loader.c
@@ -37,18 +37,19 @@
#include <sys/mman.h>
#endif
-#include "bdw-gc.h"
#include "boolean.h"
#include "bytevectors.h"
#include "elf.h"
#include "eval.h"
#include "extensions.h"
#include "gsubr.h"
+#include "gc-internal.h"
#include "list.h"
#include "pairs.h"
#include "programs.h"
#include "strings.h"
#include "threads.h"
+#include "trace.h"
#include "version.h"
#include "loader.h"
@@ -93,6 +94,43 @@
#define ELFDATA ELFDATA2LSB
#endif
+static scm_i_pthread_mutex_t roots_lock = SCM_I_PTHREAD_MUTEX_INITIALIZER;
+static size_t roots_count = 0;
+static size_t roots_capacity = 0;
+struct loader_roots { uintptr_t lo, hi; };
+static struct loader_roots *roots;
+
+static void
+add_roots(char *lo, char *hi)
+{
+ scm_i_pthread_mutex_lock (&roots_lock);
+ if (roots_count == roots_capacity)
+ {
+ roots_capacity = roots_capacity * 2 + 128;
+ size_t elt_size = sizeof(*roots);
+ struct loader_roots *new_roots = calloc (roots_capacity, elt_size);
+ // Leak the old roots; we're still O(n) as all previous root
+ // arrays sum to less than the new roots_capacity.
+ memcpy (new_roots, roots, roots_count * elt_size);
+ roots = new_roots;
+ }
+ roots[roots_count++] = (struct loader_roots){ (uintptr_t)lo, (uintptr_t)hi };
+ scm_i_pthread_mutex_unlock (&roots_lock);
+}
+
+void
+scm_trace_loader_conservative_roots (void (*trace_range)(uintptr_t lo,
+ uintptr_t hi,
+ int possibly_interior,
+ struct gc_heap *heap,
+ void *trace_data),
+ struct gc_heap *heap,
+ void *trace_data)
+{
+ for (size_t i = 0; i < roots_count; i++)
+ trace_range(roots[i].lo, roots[i].hi, 0, heap, trace_data);
+}
+
/* The page size. */
static size_t page_size;
@@ -345,7 +383,7 @@ process_dynamic_segment (char *base, Elf_Phdr *dyn_phdr,
}
if (gc_root)
- GC_add_roots (gc_root, gc_root + gc_root_size);
+ add_roots (gc_root, gc_root + gc_root_size);
*init_out = init ? pointer_to_procedure (bytecode_kind, init) : SCM_BOOL_F;
*entry_out = pointer_to_procedure (bytecode_kind, entry);
diff --git a/libguile/trace.h b/libguile/trace.h
index e05050470..d2705c112 100644
--- a/libguile/trace.h
+++ b/libguile/trace.h
@@ -29,6 +29,7 @@
struct scm_thread;
struct scm_vm;
struct gc_heap;
+struct gc_heap_roots { int unused; };
SCM_INTERNAL void
scm_trace_thread_mutator_roots (struct scm_thread *thread,
@@ -52,5 +53,14 @@ SCM_INTERNAL void scm_trace_vm (struct scm_vm *vp,
struct gc_heap *heap,
void *trace_data);
+SCM_INTERNAL void
+scm_trace_loader_conservative_roots (void (*trace_range)(uintptr_t lo,
+ uintptr_t hi,
+ int possibly_interior,
+ struct gc_heap *heap,
+ void *trace_data),
+ struct gc_heap *heap,
+ void *trace_data);
+
#endif /* SCM_THREADS_INTERNAL_H */
diff --git a/libguile/whippet-embedder.h b/libguile/whippet-embedder.h
index aa82eb4f1..82e177936 100644
--- a/libguile/whippet-embedder.h
+++ b/libguile/whippet-embedder.h
@@ -109,6 +109,31 @@ static inline void gc_trace_heap_roots (struct
gc_heap_roots *roots,
void *trace_data) {
}
+static inline void
+gc_trace_mutator_conservative_roots (struct gc_mutator_roots *roots,
+ void (*trace_range) (uintptr_t lo,
+ uintptr_t hi,
+ int
possibly_interior,
+ struct gc_heap *heap,
+ void *trace_data),
+ struct gc_heap *heap,
+ void *trace_data) {
+ /* FIXME: thread stack? Currently traced via the precise
+ gc_trace_mutator_roots. */
+}
+
+static inline void
+gc_trace_heap_conservative_roots (struct gc_heap_roots *roots,
+ void (*trace_range) (uintptr_t lo,
+ uintptr_t hi,
+ int possibly_interior,
+ struct gc_heap *heap,
+ void *trace_data),
+ struct gc_heap *heap,
+ void *trace_data) {
+ scm_trace_loader_conservative_roots(trace_range, heap, trace_data);
+}
+
static inline SCM scm_from_gc_ref (struct gc_ref ref) {
return SCM_PACK (gc_ref_value (ref));
}
