From 11ea1aba9eb99756e72b6447a93da8d901558299 Mon Sep 17 00:00:00 2001 From: Andy Wingo Date: Fri, 3 Oct 2008 16:00:30 +0200 Subject: precise stack marking, fix some missed references, still imperfect * libguile/vm-engine.h (CHECK_STACK_LEAK, NULLSTACK): Add a new mode, VM_ENABLE_STACK_NULLING, that tries to ensure that all stack data past the top of the stack is NULL. This helps to verify the VM's consistency. If VM_ENABLE_STACK_NULLING is not defined, there is no overhead. (DROP, DROPN): Hook into NULLSTACK. (POP_LIST): Hoo, fix a good bug: if CONS triggered a GC, the elements of the list that had not yet been consed would not be marked, because the sp was already below them. (NEXT): Hook into CHECK_STACK_LEAK. (INIT_ARGS): Add a note that consing the rest arg can cause GC. (NEW_FRAME): Cons up the external data after initializing the frame, so that if GC is triggered, the precise marker sees a well-formed frame. * libguile/vm-i-loader.c (load-program): In the four-integers case, use the POP macro so that we can hook into NULLSTACK (if necessary). * libguile/vm-i-scheme.c (ARGS2, ARGS3): Hook into NULLSTACK. * libguile/vm-i-system.c (halt): Null the nvalues. Rework some asserts into using ASSERT, and null the stack when we free the frame. (variable-set): Use DROPN instead of sp -= 2. (BR): Hook into NULLSTACK. (goto/args): Hook into NULLSTACK. In the non-self case, delay updating the frame until after INIT_ARGS so that GC sees a well-formed frame. Delay consing the externals until after the frame is set up, as in NEW_FRAME. (call/cc): Add some asserts. (return): Rework some asserts into ASSERT, and hook into NULLSTACK. (return/values): Hook into NULLSTACK, and use ASSERT. (return/values*) Use ASSERT. * libguile/vm.c (VM_ENABLE_ASSERTIONS, VM_ENABLE_STACK_NULLING): These are the variables that control assertions and nulling. Perhaps we can do these per-engine when we start compiling the debug engine separate from a speedy engine. (vm_mark_stack): Add a precise stack marker. Yay! (vm_cont_mark): Mark the continuation stack precisely. (capture_vm_cont): Record the difference from the vp's stack_base too, so that we can translate the dynamic links when marking the continuation stack. Memset the stack to NULL if we are doing nulling. (reinstate_vm_cont): If we are nulling, null out the relevant part of the stack. (vm_reset_stack): When resetting sp due to a nonlocal exit, null out the stack too. (vm_mark): If we are nulling, assert that there are no extra values on the stack. Mark the stack precisely. --- libguile/vm-i-scheme.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'libguile/vm-i-scheme.c') diff --git a/libguile/vm-i-scheme.c b/libguile/vm-i-scheme.c index 912c91bf2..ee724d633 100644 --- a/libguile/vm-i-scheme.c +++ b/libguile/vm-i-scheme.c @@ -47,8 +47,8 @@ */ #define ARGS1(a1) SCM a1 = sp[0]; -#define ARGS2(a1,a2) SCM a1 = sp[-1], a2 = sp[0]; sp--; -#define ARGS3(a1,a2,a3) SCM a1 = sp[-2], a2 = sp[-1], a3 = sp[0]; sp -= 2; +#define ARGS2(a1,a2) SCM a1 = sp[-1], a2 = sp[0]; sp--; NULLSTACK (1); +#define ARGS3(a1,a2,a3) SCM a1 = sp[-2], a2 = sp[-1], a3 = sp[0]; sp -= 2; NULLSTACK (2); #define RETURN(x) do { *sp = x; NEXT; } while (0) -- cgit v1.2.3