New API function to clear GC exclusion table

(part of commit 8b95edbd6 from Unity-Technologies/bdwgc)

* include/gc.h (GC_clear_exclusion_table): Declare new API function.
* mark_rts.c (GC_clear_exclusion_table): Implement.
* tests/test.c [!PCR && !GC_WIN32_THREADS && !GC_PTHREADS] (main): Call
GC_clear_exclusion_table.

3 files changed, 9 insertions, 0 deletions

diff --git a/include/gc.h b/include/gc.h
index 54d76962..fc04d90d 100644
--- a/include/gc.h
+++ b/include/gc.h
@@ -618,6 +618,9 @@ GC_API void GC_CALL GC_set_max_heap_size(GC_word /* n */);
 GC_API void GC_CALL GC_exclude_static_roots(void * /* low_address */,
                                             void * /* high_address_plus_1 */);
 
+/* Clear the number of entries in the exclusion table.  Wizards only.   */
+GC_API void GC_CALL GC_clear_exclusion_table(void);
+
 /* Clear the set of root segments.  Wizards only.                       */
 GC_API void GC_CALL GC_clear_roots(void);
 
diff --git a/mark_rts.c b/mark_rts.c
index a3fd4181..edc806a0 100644
--- a/mark_rts.c
+++ b/mark_rts.c
@@ -534,6 +534,11 @@ struct exclusion GC_excl_table[MAX_EXCLUSIONS];
 
 STATIC size_t GC_excl_table_entries = 0;/* Number of entries in use.      */
 
+GC_API void GC_CALL GC_clear_exclusion_table(void)
+{
+    GC_excl_table_entries = 0;
+}
+
 /* Return the first exclusion range that includes an address >= start_addr */
 /* Assumes the exclusion table contains at least one entry (namely the     */
 /* GC data structures).                                                    */
diff --git a/tests/test.c b/tests/test.c
index d939961f..a348c06f 100644
--- a/tests/test.c
+++ b/tests/test.c
@@ -1923,6 +1923,7 @@ void GC_CALLBACK warn_proc(char *msg, GC_word p)
       GC_noop1((GC_word)&Init);
 #   endif
     n_tests = 0;
+    GC_clear_exclusion_table(); /* no-op as called before GC init */
 #   if defined(MACOS)
         /* Make sure we have lots and lots of stack space.      */
         SetMinimumStack(cMinStackSpace);