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author | Andy Wingo <wingo@pobox.com> | 2012-03-07 10:27:16 +0100 |
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committer | Andy Wingo <wingo@pobox.com> | 2012-03-07 10:27:16 +0100 |
commit | 9d381ba4788b4d447acd3238c2fc8b86da4998b2 (patch) | |
tree | 5fd37ed1b9d73a20dbfadce6c4681bba8f05c75e /libguile/vm.c | |
parent | 3c12fc359561aedb179a524667ba03481333f482 (diff) | |
download | guile-9d381ba4788b4d447acd3238c2fc8b86da4998b2.tar.gz |
dynstack: pushing a prompt no longer allocates memory
* libguile/control.h: Remove scm_t_prompt_registers and
scm_c_make_prompt_registers.
(scm_c_abort): Take a pointer to a jmpbuf instead of a cookie. It
will serve the same purpose.
* libguile/control.c (reify_partial_continuation, scm_at_abort): Adapt
to new prompt representation.
* libguile/dynstack.h:
* libguile/dynstack.c (scm_dynstack_push_prompt): Prompts now have 5
words instead of 2, as they now push the fp, sp, ip, and jmpbuf on the
stack separately. This avoids allocation.
(scm_dynstack_find_prompt): Likewise, add return values for fp, sp,
etc.
(scm_dynstack_wind_prompt): Replaces scm_dynstack_relocate_prompt.
* libguile/eval.c (eval):
* libguile/stacks.c (find_prompt):
* libguile/throw.c (pre_init_catch): Adapt to the new prompt mechanism.
* libguile/vm-engine.c (vm_engine): Setjmp an on-stack jmpbuf every time
the VM enters. We can then re-use that jmpbuf for all prompts in that
invocation.
* libguile/vm-i-system.c (partial_cont_call): Adapt to change in prompt
representation. We don't need to wind here any more, since we pass in
the prompt's jmpbuf.
(prompt): Adapt to scm_dynstack_push_prompt change.
(abort): Adapt to vm_abort change.
* libguile/vm.h (struct scm_vm): No more cookie.
* libguile/vm.c (vm_abort): Adapt to scm_c_abort change.
(vm_reinstate_partial_continuation): Rewind the dynamic stack here,
now that we do have a valid jmpbuf.
(make_vm): No need to initialize a cookie.
Diffstat (limited to 'libguile/vm.c')
-rw-r--r-- | libguile/vm.c | 44 |
1 files changed, 27 insertions, 17 deletions
diff --git a/libguile/vm.c b/libguile/vm.c index a283857f0..4d32c9545 100644 --- a/libguile/vm.c +++ b/libguile/vm.c @@ -247,9 +247,11 @@ vm_dispatch_hook (SCM vm, int hook_num) vp->trace_level = saved_trace_level; } -static void vm_abort (SCM vm, size_t n, scm_t_int64 cookie) SCM_NORETURN; static void -vm_abort (SCM vm, size_t n, scm_t_int64 vm_cookie) +vm_abort (SCM vm, size_t n, scm_i_jmp_buf *current_registers) SCM_NORETURN; + +static void +vm_abort (SCM vm, size_t n, scm_i_jmp_buf *current_registers) { size_t i; ssize_t tail_len; @@ -272,12 +274,13 @@ vm_abort (SCM vm, size_t n, scm_t_int64 vm_cookie) /* NULLSTACK (n + 1) */ SCM_VM_DATA (vm)->sp -= n + 1; - scm_c_abort (vm, tag, n + tail_len, argv, vm_cookie); + scm_c_abort (vm, tag, n + tail_len, argv, current_registers); } -static scm_t_ptrdiff -vm_reinstate_partial_continuation (SCM vm, SCM cont, - size_t n, SCM *argv, scm_t_int64 vm_cookie) +static void +vm_reinstate_partial_continuation (SCM vm, SCM cont, size_t n, SCM *argv, + scm_t_dynstack *dynstack, + scm_i_jmp_buf *registers) { struct scm_vm *vp; struct scm_vm_cont *cp; @@ -325,16 +328,24 @@ vm_reinstate_partial_continuation (SCM vm, SCM cont, vp->sp++; *vp->sp = scm_from_size_t (n); - /* Finally, rewind the dynamic state. Unhappily, we have to do this - in the vm_engine. If we do it here, the stack frame will likely - have been stompled by some future call out of the VM, so we will - return to some other part of the VM. - - We used to wind and relocate the prompts here, but that's bogus, - because a rewinder would then be able to abort to a prompt with a - stale jmpbuf. */ - - return reloc; + /* The prompt captured a slice of the dynamic stack. Here we wind + those entries onto the current thread's stack. We also have to + relocate any prompts that we see along the way. */ + { + scm_t_bits *walk; + + for (walk = SCM_DYNSTACK_FIRST (cp->dynstack); + SCM_DYNSTACK_TAG (walk); + walk = SCM_DYNSTACK_NEXT (walk)) + { + scm_t_bits tag = SCM_DYNSTACK_TAG (walk); + + if (SCM_DYNSTACK_TAG_TYPE (tag) == SCM_DYNSTACK_TYPE_PROMPT) + scm_dynstack_wind_prompt (dynstack, walk, reloc, registers); + else + scm_dynstack_wind_1 (dynstack, walk); + } + } #undef RELOC } @@ -522,7 +533,6 @@ make_vm (void) vp->trace_level = 0; for (i = 0; i < SCM_VM_NUM_HOOKS; i++) vp->hooks[i] = SCM_BOOL_F; - vp->cookie = 0; return scm_cell (scm_tc7_vm, (scm_t_bits)vp); } #undef FUNC_NAME |