From d7d87bae1aa90cbec5214110c0eb3bcfdd835ca9 Mon Sep 17 00:00:00 2001
From: Douglas Katzman <dougk@google.com>
Date: Wed, 12 Apr 2017 12:56:08 -0400
Subject: [PATCH] Accept generalized "stop" flag from callback in
 walk_generation()

---
 src/runtime/gencgc-internal.h |  4 ++--
 src/runtime/gencgc.c          | 19 ++++++++++++++-----
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/src/runtime/gencgc-internal.h b/src/runtime/gencgc-internal.h
index f266acb15..0cf8e3afd 100644
--- a/src/runtime/gencgc-internal.h
+++ b/src/runtime/gencgc-internal.h
@@ -267,6 +267,6 @@ extern boolean gencgc_partial_pickup;
 
 #endif
 
-extern void
-walk_generation(void (*proc)(lispobj*,lispobj*),
+extern uword_t
+walk_generation(uword_t (*proc)(lispobj*,lispobj*),
                 generation_index_t generation);
diff --git a/src/runtime/gencgc.c b/src/runtime/gencgc.c
index 5ebe4d84c..797659108 100644
--- a/src/runtime/gencgc.c
+++ b/src/runtime/gencgc.c
@@ -3204,8 +3204,9 @@ verify_range(lispobj *start, size_t words)
         start += count;
     }
 }
-static void verify_space(lispobj *start, lispobj *end) {
+static uword_t verify_space(lispobj *start, lispobj *end) {
     verify_range(start, end-start);
+    return 0;
 }
 
 static void verify_dynamic_space();
@@ -3243,8 +3244,11 @@ verify_gc(void)
     verify_dynamic_space();
 }
 
-void
-walk_generation(void (*proc)(lispobj*,lispobj*),
+/* Call 'proc' with pairs of addresses demarcating ranges in the
+ * specified generation.
+ * Stop if any invocation returns non-zero, and return that value */
+uword_t
+walk_generation(uword_t (*proc)(lispobj*,lispobj*),
                 generation_index_t generation)
 {
     page_index_t i;
@@ -3270,11 +3274,16 @@ walk_generation(void (*proc)(lispobj*,lispobj*),
                 if (page_ends_contiguous_block_p(last_page, page_table[i].gen))
                     break;
 
-            proc(page_address(i), (lispobj*)((char*)page_address(last_page) +
-                                             page_bytes_used(last_page)));
+            uword_t result =
+                proc(page_address(i),
+                     (lispobj*)(page_bytes_used(last_page)
+                                + (char*)page_address(last_page)));
+            if (result) return result;
+
             i = last_page;
         }
     }
+    return 0;
 }
 static void verify_generation(generation_index_t generation)
 {
-- 
2.11.4.GIT