From 05af441d05ade5408f7c4532b0f4e5818ecf5e35 Mon Sep 17 00:00:00 2001
From: David Jones
Date: Wed, 9 Jul 2003 16:42:29 +0100
Subject: Mps: can now call mps_arena_has_addr during

mps_arena_formatted_objects_walk.  test walkt0 is witness

Copied from Perforce
 Change: 50108
 ServerID: perforce.ravenbrook.com

---
 mps/code/global.c | 36 ++++++++++++++++++++++++++++++++----
 mps/code/mpm.h    |  2 ++
 mps/code/mpsi.c   |  7 +++++--
 3 files changed, 39 insertions(+), 6 deletions(-)

(limited to 'mps/code')

diff --git a/mps/code/global.c b/mps/code/global.c
index db4a9f2fd0d..051ba680480 100644
--- a/mps/code/global.c
+++ b/mps/code/global.c
@@ -36,6 +36,9 @@ SRCID(global, "$Id$");
 static Bool arenaRingInit = FALSE;
 static RingStruct arenaRing;       /* <design/arena/#static.ring> */
 
+/* forward declarations */
+void arenaEnterLock(Arena, void (*)(Lock));
+void arenaLeaveLock(Arena, void (*)(Lock));
 
 /* ArenaControlPool -- get the control pool */
 
@@ -421,15 +424,31 @@ void (ArenaEnter)(Arena arena)
 #else
 void ArenaEnter(Arena arena)
 {
+  arenaEnterLock(arena, LockClaim);
+}
+#endif
+
+void arenaEnterLock(Arena arena, void (*lock)(Lock))
+{
+  /* This check is safe to do outside the lock.  Unless the client
+     is also calling ArenaDestroy, but that's a protocol violation by
+     the client if so. */
   AVER(CHECKT(Arena, arena));
 
   StackProbe(StackProbeDEPTH);
-  LockClaim(ArenaGlobals(arena)->lock);
+  lock(ArenaGlobals(arena)->lock);
   AVERT(Arena, arena); /* can't AVER it until we've got the lock */
   ShieldEnter(arena);
 }
-#endif
 
+/* Same as ArenaEnter, but for the few functions that need to be
+   reentrant with respect to some part of the MPS.
+   For example, mps_arena_has_addr. */
+
+void ArenaEnterRecursive(Arena arena)
+{
+  arenaEnterLock(arena, LockClaimRecursive);
+}
 
 /* ArenaLeave -- leave the state where you can look at MPM data structures */
 
@@ -441,14 +460,23 @@ void (ArenaLeave)(Arena arena)
 }
 #else
 void ArenaLeave(Arena arena)
+{
+  arenaLeaveLock(arena, LockReleaseMPM);
+}
+#endif
+
+void arenaLeaveLock(Arena arena, void (*unlock)(Lock))
 {
   AVERT(Arena, arena);
   ShieldLeave(arena);
   ProtSync(arena);              /* <design/prot/#if.sync> */
-  LockReleaseMPM(ArenaGlobals(arena)->lock);
+  unlock(ArenaGlobals(arena)->lock);
 }
-#endif
 
+void ArenaLeaveRecursive(Arena arena)
+{
+  arenaLeaveLock(arena, LockReleaseRecursive);
+}
 
 /* mps_exception_info -- pointer to exception info
  *
diff --git a/mps/code/mpm.h b/mps/code/mpm.h
index c2b88250774..e29a902ea32 100644
--- a/mps/code/mpm.h
+++ b/mps/code/mpm.h
@@ -463,6 +463,8 @@ extern void (ArenaLeave)(Arena arena);
 #define ArenaLeave(arena)  UNUSED(arena)
 #endif
 
+extern void ArenaEnterRecursive(Arena arena);
+extern void ArenaLeaveRecursive(Arena arena);
 
 extern void (ArenaPoll)(Globals globals);
 #ifdef MPS_PROD_EPCORE
diff --git a/mps/code/mpsi.c b/mps/code/mpsi.c
index 316ff6cf03e..d855a68de41 100644
--- a/mps/code/mpsi.c
+++ b/mps/code/mpsi.c
@@ -451,10 +451,13 @@ mps_bool_t mps_arena_has_addr(mps_arena_t mps_arena, mps_addr_t p)
     Bool b;
     Arena arena = (Arena)mps_arena;
 
-    ArenaEnter(arena);
+    /* One of the few functions that can be called
+       during the call to an MPS function.  IE this function
+       can be called when walking the heap. */
+    ArenaEnterRecursive(arena);
     AVERT(Arena, arena);
     b = ArenaHasAddr(arena, (Addr)p);
-    ArenaLeave(arena);
+    ArenaLeaveRecursive(arena);
     return b;
 }
 
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