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author | Andy Wingo <wingo@pobox.com> | 2008-10-09 14:44:43 +0200 |
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committer | Andy Wingo <wingo@pobox.com> | 2008-10-09 14:44:43 +0200 |
commit | 66db076ae17e1a6b5225fabaaeb6958115cc9b4c (patch) | |
tree | a2390479cac342ab6de5d38aa9492648afe74f16 /libguile/vm-engine.h | |
parent | 0570c3f197f910cc136969d6a2ed2ad0792b3501 (diff) | |
download | guile-66db076ae17e1a6b5225fabaaeb6958115cc9b4c.tar.gz |
NULLSTACK fixes for nonlocal exits in reentrant pre-wind handlers
* libguile/vm-i-system.c (goto/cc): Add some asserts here.
* libguile/vm.c (capture_vm_cont): Add some asserts here too.
(reinstate_vm_cont): Null the correct number of bytes. Add a FIXME.
(vm_reset_stack): Make the code a bit clearer. Null the correct number
of bytes.
* libguile/vm-engine.h (NULLSTACK_FOR_NONLOCAL_EXIT): New macro, handles
a very tricky case that took me days to find! Amply commented. Expands
to nothing in the normal case.
* libguile/vm-i-system.c (call, goto/args, mv-call): Call
NULLSTACK_FOR_NONLOCAL_EXIT in the right places. Fixes
continuations.test.
Diffstat (limited to 'libguile/vm-engine.h')
-rw-r--r-- | libguile/vm-engine.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/libguile/vm-engine.h b/libguile/vm-engine.h index 2c15b9d63..22a7ef5e4 100644 --- a/libguile/vm-engine.h +++ b/libguile/vm-engine.h @@ -247,10 +247,17 @@ # define CHECK_STACK_LEAKN(_n) ASSERT (!sp[_n]); # define CHECK_STACK_LEAK() CHECK_STACK_LEAKN(1) # define NULLSTACK(_n) { int __x = _n; CHECK_STACK_LEAKN (_n+1); while (__x > 0) sp[__x--] = NULL; } +/* If you have a nonlocal exit in a pre-wind proc while invoking a continuation + inside a dynwind (phew!), the stack is fully rewound but vm_reset_stack for + that continuation doesn't have a chance to run. It's not important on a + semantic level, but it does mess up our stack nulling -- so this macro is to + fix that. */ +# define NULLSTACK_FOR_NONLOCAL_EXIT() if (vp->sp > sp) NULLSTACK (vp->sp - sp); #else # define CHECK_STACK_LEAKN(_n) # define CHECK_STACK_LEAK() # define NULLSTACK(_n) +# define NULLSTACK_FOR_NONLOCAL_EXIT() #endif #define CHECK_OVERFLOW() \ |