Make mps_arena_step suitable for purpose: arenastep now calls tracestartcollectall directly (not via arenastartcollect) so that it no longer unclamps the arena as a side effect.

Add test case: steptest now runs with the arena clamped, and checks that mps_arena_step does not unclamp it.

Copied from Perforce
 Change: 181098
 ServerID: perforce.ravenbrook.com

2 files changed, 10 insertions, 3 deletions

diff --git a/mps/code/global.c b/mps/code/global.c
index ed297978d64..2a8ec4e4d3b 100644
--- a/mps/code/global.c
+++ b/mps/code/global.c
@@ -788,9 +788,13 @@ Bool ArenaStep(Globals globals, double interval, double multiplier)
   if (arenaShouldCollectWorld(arena, interval, multiplier,
                               start, clocks_per_sec))
   {
-    ArenaStartCollect(globals, TraceStartWhyOPPORTUNISM);
-    arena->lastWorldCollect = start;
-    stepped = TRUE;
+    Res res;
+    Trace trace;
+    res = TraceStartCollectAll(&trace, arena, TraceStartWhyOPPORTUNISM);
+    if (res == ResOK) {
+      arena->lastWorldCollect = start;
+      stepped = TRUE;
+    }
   }
 
   /* loop while there is work to do and time on the clock. */
diff --git a/mps/code/steptest.c b/mps/code/steptest.c
index 1905a141037..61ec888801b 100644
--- a/mps/code/steptest.c
+++ b/mps/code/steptest.c
@@ -9,6 +9,7 @@
 #include "fmtdy.h"
 #include "fmtdytst.h"
 #include "testlib.h"
+#include "mpm.h"
 #include "mpscamc.h"
 #include "mpsavm.h"
 #include "mpstd.h"
@@ -278,6 +279,7 @@ static void test_step(mps_arena_t arena, double multiplier)
     mps_bool_t res;
     double t1 = my_clock();
     res = mps_arena_step(arena, 0.1, multiplier);
+    cdie(ArenaGlobals(arena)->clamped, "arena was unclamped");
     t1 = time_since(t1);
     if (res) {
         if (t1 > max_step_time)
@@ -500,6 +502,7 @@ int main(int argc, char *argv[])
         die(mps_arena_create(&arena, mps_arena_class_vm(),
                              testArenaSIZE),
             "arena_create");
+        mps_arena_clamp(arena);
         die(mps_thread_reg(&thread, arena), "thread_reg");
         mps_tramp(&r, test, arena, 0);
         mps_thread_dereg(thread);