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authorAndy Wingo <wingo@pobox.com>2008-12-26 17:59:46 +0100
committerAndy Wingo <wingo@pobox.com>2008-12-26 18:07:20 +0100
commitb1b942b74c0f2a9870326372843ea1baeafc3dcb (patch)
tree7948d7b0472ad88b4a3919c84fd72d16ce8c448f /libguile/vm-engine.h
parent9f0e9918f4475d1a6313a8328262e80758c7f64e (diff)
downloadguile-b1b942b74c0f2a9870326372843ea1baeafc3dcb.tar.gz
remove heap links in VM frames, incorporate vm frames into normal backtraces
* doc/ref/vm.texi (Stack Layout): Update to remove references to the "heap link". * gdbinit: Update for "heap link" removal. * libguile/frames.c: * libguile/frames.h: Update macros and diagram for removal of "heap link". As part of this, we also remove "heap frames", replacing them with "vm frames", which are much like the interpreter's debug objects, but for VM stacks. That is to say, they don't actually hold the stack themselves, just the pointers into stack that's held by a continuation (either captured or current). * libguile/stacks.c (stack_depth, read_frames): Since a "stack" object is really a copy of information that comes from somewhere else, it makes sense to copy over info from the VM, just as `make-stack' does from the evaluator. The tricky bit is to figure out how to interleave VM and interpreter frames. We do that by starting in the interpreter, and whenever the current frame's procedure is actually a program, we switch to the VM stack, switching back when we reach a "bootstrap frame". The last bit is hacky, but it does work... (is_vm_bootstrap_frame): Hacky predicate to see if a VM frame is a bootstrap frame. (scm_make_stack): Accept a VM frame in addition to debug frames. Probably has some bugs in this case. But in the case that the arg is #t (a common case), do the right thing, capturing the top VM frame as well, and interleaving those frames appropriately on the stack. As an accident, we lost the ability to limit the number of frames in the backtrace. We could add that back, but personally I always want *all* frames in the trace... Narrowing still works fine, though there are some hiccups sometimes -- e.g. an outer cut to a procedure that does a tail-call in VM code will never find the cut, as it no longer exists in the continuation. * libguile/vm.h (struct scm_vm): So! Now that we have switched to save stacks in the normal make-stack, there's no more need for `this_frame' or `last_frame'. On the other hand, we can take this opportunity to fix tracing: when we're in a trace hook, we set `trace_frame' on the VM, so we know not to fire hooks when we're already in a hook. (struct scm_vm_cont): Expose this, as make-stack needs it to make VM frames from VM continuations. * libguile/vm.c (scm_vm_trace_frame): New function, gets the current trace frame. (vm_mark, make_vm): Hook up the trace frame. (vm_dispatch_hook): New hook dispatcher, with a dynwind so it does the right thing if the hook exits nonlocally. * libguile/vm-engine.c (vm_run): No more this_frame in the wind data. * libguile/vm-engine.h (RUN_HOOK): Run hooks through the dispatcher. (ALIGN_AS_NON_IMMEDIATE, POP_LIST_ON_STACK): Remove unused code. (NEW_FRAME): Adapt for no HL in the frame. * libguile/vm-i-system.c (goto/args, mv-call, return, return/values): Adapt for no HL in the frame. * module/system/vm/frame.scm: * module/system/vm/vm.scm: Beginnings of some reworkings, needs more thought.
Diffstat (limited to 'libguile/vm-engine.h')
-rw-r--r--libguile/vm-engine.h83
1 files changed, 6 insertions, 77 deletions
diff --git a/libguile/vm-engine.h b/libguile/vm-engine.h
index 215f630b1..217ad2e66 100644
--- a/libguile/vm-engine.h
+++ b/libguile/vm-engine.h
@@ -217,11 +217,10 @@
#if VM_USE_HOOKS
#define RUN_HOOK(h) \
{ \
- if (!SCM_FALSEP (vp->hooks[h])) \
+ if (SCM_UNLIKELY (!SCM_FALSEP (vp->hooks[h])))\
{ \
SYNC_REGISTER (); \
- vm_heapify_frames (vm); \
- scm_c_run_hook (vp->hooks[h], hook_args); \
+ vm_dispatch_hook (vm, vp->hooks[h], hook_args); \
CACHE_REGISTER (); \
} \
}
@@ -312,75 +311,6 @@ do \
} while (0)
-/* Below is a (slightly broken) experiment to avoid calling `scm_cell' and to
- allocate cells on the stack. This is a significant improvement for
- programs which call a lot of procedures, since the procedure call
- mechanism uses POP_LIST which normally uses `scm_cons'.
-
- What it does is that it creates a list whose cells are allocated on the
- VM's stack instead of being allocated on the heap via `scm_cell'. This is
- much faster. However, if the callee does something like:
-
- (lambda (. args)
- (set! the-args args))
-
- then terrible things may happen since the list of arguments may be
- overwritten later on. */
-
-
-/* Awful hack that aligns PTR so that it can be considered as a non-immediate
- value by Guile. */
-#define ALIGN_AS_NON_IMMEDIATE(_ptr) \
-{ \
- if ((scm_t_bits)(_ptr) & 6) \
- { \
- size_t _incr; \
- \
- _incr = (scm_t_bits)(_ptr) & 6; \
- _incr = (~_incr) & 7; \
- (_ptr) += _incr; \
- } \
-}
-
-#define POP_LIST_ON_STACK(n) \
-do \
-{ \
- int i; \
- if (n == 0) \
- { \
- sp -= n; \
- PUSH (SCM_EOL); \
- } \
- else \
- { \
- SCM *list_head, *list; \
- \
- list_head = sp + 1; \
- ALIGN_AS_NON_IMMEDIATE (list_head); \
- list = list_head; \
- \
- sp -= n; \
- for (i = 1; i <= n; i++) \
- { \
- /* The cell's car and cdr. */ \
- *(list) = sp[i]; \
- *(list + 1) = PTR2SCM (list + 2); \
- list += 2; \
- } \
- \
- /* The last pair's cdr is '(). */ \
- list--; \
- *list = SCM_EOL; \
- /* Push the SCM object that points */ \
- /* to the first cell. */ \
- PUSH (PTR2SCM (list_head)); \
- } \
-} \
-while (0)
-
-/* end of the experiment */
-
-
#define POP_LIST_MARK() \
do { \
SCM o; \
@@ -476,7 +406,7 @@ do { \
/* New registers */ \
fp = sp - bp->nargs + 1; \
data = SCM_FRAME_DATA_ADDRESS (fp); \
- sp = data + 4; \
+ sp = data + 3; \
CHECK_OVERFLOW (); \
stack_base = sp; \
ip = bp->base; \
@@ -486,10 +416,9 @@ do { \
data[-i] = SCM_UNDEFINED; \
\
/* Set frame data */ \
- data[4] = (SCM)ra; \
- data[3] = 0x0; \
- data[2] = (SCM)dl; \
- data[1] = SCM_BOOL_F; \
+ data[3] = (SCM)ra; \
+ data[2] = 0x0; \
+ data[1] = (SCM)dl; \
\
/* Postpone initializing external vars, \
because if the CONS causes a GC, we \