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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/stacks.c
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/stacks.c')
-rw-r--r--libguile/stacks.c104
1 files changed, 88 insertions, 16 deletions
diff --git a/libguile/stacks.c b/libguile/stacks.c
index 4b97a1827..85527bd6a 100644
--- a/libguile/stacks.c
+++ b/libguile/stacks.c
@@ -32,6 +32,9 @@
#include "libguile/modules.h"
#include "libguile/root.h"
#include "libguile/strings.h"
+#include "libguile/vm.h" /* to capture vm stacks */
+#include "libguile/frames.h" /* vm frames */
+#include "libguile/instructions.h" /* scm_op_halt */
#include "libguile/validate.h"
#include "libguile/stacks.h"
@@ -123,19 +126,24 @@
#define RELOC_FRAME(ptr, offset) \
((scm_t_debug_frame *) ((SCM_STACKITEM *) (ptr) + (offset)))
+/* FIXME: factor this out somewhere? */
+static int is_vm_bootstrap_frame (SCM f)
+{
+ struct scm_program *bp = SCM_PROGRAM_DATA (scm_vm_frame_program (f));
+ return bp->base[bp->size-1] == scm_op_halt;
+}
/* Count number of debug info frames on a stack, beginning with
* DFRAME. OFFSET is used for relocation of pointers when the stack
* is read from a continuation.
*/
-static scm_t_bits
-stack_depth (scm_t_debug_frame *dframe, scm_t_ptrdiff offset,
- SCM *id, int *maxp)
+static long
+stack_depth (scm_t_debug_frame *dframe, scm_t_ptrdiff offset, SCM vmframe,
+ SCM *id)
{
long n;
- long max_depth = SCM_BACKTRACE_MAXDEPTH;
for (n = 0;
- dframe && !SCM_VOIDFRAMEP (*dframe) && n < max_depth;
+ dframe && !SCM_VOIDFRAMEP (*dframe);
dframe = RELOC_FRAME (dframe->prev, offset))
{
if (SCM_EVALFRAMEP (*dframe))
@@ -148,15 +156,32 @@ stack_depth (scm_t_debug_frame *dframe, scm_t_ptrdiff offset,
if ((((info - vect) & 1) == 0)
&& SCM_OVERFLOWP (*dframe)
&& !SCM_UNBNDP (info[1].a.proc))
- ++n;
+ ++n;
}
+ else if (SCM_APPLYFRAMEP (*dframe))
+ {
+ scm_t_debug_info *vect = RELOC_INFO (dframe->vect, offset);
+ if (SCM_PROGRAM_P (vect[0].a.proc))
+ {
+ /* count vmframe back to previous bootstrap frame */
+ for (; scm_is_true (vmframe); vmframe = scm_c_vm_frame_prev (vmframe))
+ {
+ if (is_vm_bootstrap_frame (vmframe))
+ { /* skip bootstrap frame, cut out of the vm backtrace */
+ vmframe = scm_c_vm_frame_prev (vmframe);
+ break;
+ }
+ else
+ ++n;
+ }
+ }
+ ++n; /* increment for apply frame in any case */
+ }
else
++n;
}
if (dframe && SCM_VOIDFRAMEP (*dframe))
*id = RELOC_INFO(dframe->vect, offset)[0].id;
- else if (dframe)
- *maxp = 1;
return n;
}
@@ -234,7 +259,7 @@ do { \
static scm_t_bits
read_frames (scm_t_debug_frame *dframe, scm_t_ptrdiff offset,
- long n, scm_t_info_frame *iframes)
+ SCM vmframe, long n, scm_t_info_frame *iframes)
{
scm_t_info_frame *iframe = iframes;
scm_t_debug_info *info, *vect;
@@ -298,6 +323,32 @@ read_frames (scm_t_debug_frame *dframe, scm_t_ptrdiff offset,
continue;
else
{
+ if (SCM_PROGRAM_P (iframe->proc))
+ {
+ scm_t_info_frame saved = *iframe;
+ for (; scm_is_true (vmframe);
+ vmframe = scm_c_vm_frame_prev (vmframe))
+ {
+ if (is_vm_bootstrap_frame (vmframe))
+ { /* skip bootstrap frame, back to interpreted frames */
+ vmframe = scm_c_vm_frame_prev (vmframe);
+ break;
+ }
+ else
+ {
+ /* Oh dear, oh dear, oh dear. */
+ iframe->flags = SCM_UNPACK (SCM_INUM0) | SCM_FRAMEF_PROC;
+ iframe->source = scm_vm_frame_source (vmframe);
+ iframe->proc = scm_vm_frame_program (vmframe);
+ iframe->args = scm_vm_frame_arguments (vmframe);
+ ++iframe;
+ if (--n == 0)
+ goto quit;
+ }
+ }
+ *iframe = saved;
+ }
+
NEXT_FRAME (iframe, n, quit);
}
quit:
@@ -431,6 +482,7 @@ SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
int maxp;
scm_t_debug_frame *dframe;
scm_t_info_frame *iframe;
+ SCM vmframe;
long offset = 0;
SCM stack, id;
SCM inner_cut, outer_cut;
@@ -439,17 +491,37 @@ SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
scm_make_stack was given. */
if (scm_is_eq (obj, SCM_BOOL_T))
{
+ struct scm_vm *vp = SCM_VM_DATA (scm_the_vm ());
dframe = scm_i_last_debug_frame ();
+ vmframe = scm_c_make_vm_frame (scm_the_vm (), vp->fp, vp->sp, vp->ip, 0);
}
else if (SCM_DEBUGOBJP (obj))
{
dframe = SCM_DEBUGOBJ_FRAME (obj);
+ vmframe = SCM_BOOL_F;
+ }
+ else if (SCM_VM_FRAME_P (obj))
+ {
+ dframe = NULL;
+ vmframe = obj;
}
else if (SCM_CONTINUATIONP (obj))
{
scm_t_contregs *cont = SCM_CONTREGS (obj);
offset = cont->offset;
dframe = RELOC_FRAME (cont->dframe, offset);
+ if (!scm_is_null (cont->vm_conts))
+ { SCM vm_cont;
+ struct scm_vm_cont *data;
+ vm_cont = scm_cdr (scm_car (cont->vm_conts));
+ data = SCM_VM_CONT_DATA (vm_cont);
+ vmframe = scm_c_make_vm_frame (vm_cont,
+ data->stack_base + data->fp,
+ data->stack_base + data->sp,
+ data->ip,
+ data->reloc);
+ } else
+ vmframe = SCM_BOOL_F;
}
else
{
@@ -462,7 +534,8 @@ SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
(SCM_BACKTRACE_MAXDEPTH). */
id = SCM_BOOL_F;
maxp = 0;
- n = stack_depth (dframe, offset, &id, &maxp);
+ n = stack_depth (dframe, offset, vmframe, &id);
+ /* FIXME: redo maxp? */
size = n * SCM_FRAME_N_SLOTS;
/* Make the stack object. */
@@ -472,7 +545,7 @@ SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
SCM_STACK (stack) -> frames = iframe;
/* Translate the current chain of stack frames into debugging information. */
- n = read_frames (dframe, offset, n, iframe);
+ n = read_frames (dframe, offset, vmframe, n, iframe);
SCM_STACK (stack) -> length = n;
/* Narrow the stack according to the arguments given to scm_make_stack. */
@@ -500,12 +573,11 @@ SCM_DEFINE (scm_make_stack, "make-stack", 1, 0, 1,
n = SCM_STACK (stack) -> length;
}
+ if (n > 0 && maxp)
+ iframe[n - 1].flags |= SCM_FRAMEF_OVERFLOW;
+
if (n > 0)
- {
- if (maxp)
- iframe[n - 1].flags |= SCM_FRAMEF_OVERFLOW;
- return stack;
- }
+ return stack;
else
return SCM_BOOL_F;
}