Changeset 6315

Timestamp:

Apr 20, 2007, 2:01:17 AM (18 years ago)

Author:

Gary Byers

Message:

mark_xp: if rip is unmarked and tagged as a return address, treat
it as one. (It's generally possible for RIP to be tagged as anything,
but except in the case of returning to the instruction which reloads
FN from RIP, some other register in the exception frame should cause
the instruction pointer to have been marked.) We need to do this,
since we're relaxing the restriction that ra0 always contain a return
address on function return.

File:

• branches/x8664-call/ccl/lisp-kernel/x86-gc.c (modified) (2 diffs)

branches/x8664-call/ccl/lisp-kernel/x86-gc.c

@@ -1467 +1467 @@
 mark_xp(ExceptionInformation *xp)
 {
-  natural *regs = (natural *) xpGPRvector(xp);
-
+  natural *regs = (natural *) xpGPRvector(xp), dnode;
+  LispObj rip;
+    
+  
 
   mark_root(regs[Iarg_z]);
@@ -1482 +1484 @@
   mark_root(regs[Itemp1]);
   mark_root(regs[Itemp2]);
-  /* If the IP isn't pointing into a marked function,
-     we're in big trouble.  Check for that here ? */
+  /* If the RIP isn't pointing into a marked function,
+     we can -maybe- recover from that if it's tagged as
+     a TRA. */
+  rip = regs[Iip];
+  dnode = gc_area_dnode(rip);
+  if ((dnode < GCndnodes_in_area) &&
+      (! ref_bit(GCmarkbits,dnode))) {
+    if (tag_of(rip) == tag_tra) {
+      mark_root(rip);
+    } else {
+      Bug(NULL, "Can't find function for rip 0x%16lx",rip);
+    }
+  }
 }