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authorAndy Wingo <wingo@pobox.com>2015-09-22 10:24:30 +0000
committerAndy Wingo <wingo@pobox.com>2015-10-21 11:49:20 +0200
commit0007507340b10754cb307763cbc8eeb064853926 (patch)
treeffce65ab7dd195fa2f45360bef7d9db62760ce67 /libguile/continuations.c
parentd7199da8c9d287b9602e053d470d0a822b4f7cec (diff)
downloadguile-0007507340b10754cb307763cbc8eeb064853926.tar.gz
VM stack grows downward
Adapt VM stack to grow downward. This will make native compilation look more like the VM code, as we will be able to use native CALL instructions, taking proper advantage of the return address buffer. * libguile/continuations.c (scm_i_continuation_to_frame): Record offsets from stack top. * libguile/control.c (scm_i_prompt_pop_abort_args_x): Adapt for reversed order of arguments, and instead of relying on the abort to push on the number of arguments, make the caller save the stack depth, which allows us to compute the number of arguments ourselves. (reify_partial_continuation, scm_c_abort): Adapt to reversed stack order. * libguile/dynstack.c (scm_dynstack_wind_prompt): Since we wind the stack in a downward direction, subtract the reloc instead of adding it. * libguile/dynstack.h (SCM_F_DYNSTACK_PROMPT_ESCAPE_ONLY): Remove flag; instead rely on prompt-establishing code to save the stack depth. * libguile/eval.c (eval): Remove extraneous "volatile" declarations for variables that are not re-set between the setjmp and any longjmp. Adapt to save stack depth before instating the prompt. * libguile/foreign.c (scm_i_foreign_call): Adapt to receive arguments in reverse order. * libguile/frames.c (frame_stack_top, scm_i_frame_stack_top): Adapt to compute stack top instead of stack bottom. (scm_c_frame_closure): Adapt to stack growth change. (scm_frame_num_locals, scm_frame_local_ref, scm_frame_set_x): Use union data type to access stack. (RELOC): Reformat. (scm_c_frame_previous): Adapt to stack growth change. * libguile/frames.h: Adapt stack diagram to indicate that the stack grows up. (union scm_vm_stack_element): New data type used to access items on the stack. (SCM_FRAME_PREVIOUS_SP) (SCM_FRAME_RETURN_ADDRESS, SCM_FRAME_SET_RETURN_ADDRESS) (SCM_FRAME_DYNAMIC_LINK, SCM_FRAME_SET_DYNAMIC_LINK) (SCM_FRAME_LOCAL, SCM_FRAME_NUM_LOCALS): Adapt to stack representation change. (SCM_FRAME_SLOT): New helper. (SCM_VM_FRAME_FP, SCM_VM_FRAME_SP): Adapt to stack growth change. * libguile/stacks.c (scm_make_stack): Record offsets from top of stack. * libguile/throw.c (catch): Adapt to scm_i_prompt_pop_abort_args_x change. * libguile/vm-engine.c (ALLOC_FRAME, RESET_FRAME): (FRAME_LOCALS_COUNT_FROM): Adapt to stack growth change. (LOCAL_ADDRESS): Use SCM_FRAME_SLOT to get the address as the proper data type. (RETURN_ONE_VALUE, RETURN_VALUE_LIST): Adapt to stack growth change. (apply): Shuffling up the SMOB apply args can cause the stack to expand, so use ALLOC_FRAME instead of RESET_FRAME. (vm_engine): Adapt for stack growth change. * libguile/vm.c (vm_increase_sp, vm_push_sp, vm_restore_sp): Adapt to stack representation change. (scm_i_vm_cont_to_frame): Adapt to take offsets from the top. (scm_i_vm_capture_stack): Adapt to capture from the top. (vm_return_to_continuation_inner): Adapt for data type changes. (vm_return_to_continuation): Likewise, and instead of looping, just splat the saved arguments on with memcpy. (vm_dispatch_hook): Adapt to receive arguments in the reverse order. Adapt callers. (vm_abort): There is never a tail argument. Adapt to stack representation change. (vm_reinstate_partial_continuation) (vm_reinstate_partial_continuation_inner): Adapt to stack growth change. (allocate_stack, free_stack): Adapt to data type change. (expand_stack): Don't try to mremap(), as you can't grow a mapping from the bottom. Without knowing that there's a free mapping space right below the old stack, which there usually isn't on Linux, we have to copy. We can't use MAP_GROWSDOWN because Linux is buggy. (make_vm): Adapt to stack representation changes. (return_unused_stack_to_os): Round down instead of up, as the stack grows down. (scm_i_vm_mark_stack): Adapt to walk up the stack. (scm_i_vm_free_stack): Adapt to scm_vm changes. (vm_expand_stack_inner, reset_stack_limit, vm_expand_stack): Adapt to the stack growing down. (scm_call_n): Adapt to the stack growing down. Don't allow argv to point into the stack. * libguile/vm.h (struct scm_vm, struct scm_vm_cont): Adapt to hold the stack top and bottom.
Diffstat (limited to 'libguile/continuations.c')
-rw-r--r--libguile/continuations.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/libguile/continuations.c b/libguile/continuations.c
index 8dca62e2d..7cc3cea10 100644
--- a/libguile/continuations.c
+++ b/libguile/continuations.c
@@ -180,10 +180,13 @@ scm_i_continuation_to_frame (SCM continuation, struct scm_frame *frame)
if (scm_is_true (cont->vm_cont))
{
struct scm_vm_cont *data = SCM_VM_CONT_DATA (cont->vm_cont);
+ union scm_vm_stack_element *stack_top;
+ /* FIXME vm_cont should hold fp/sp offsets */
+ stack_top = data->stack_bottom + data->stack_size;
frame->stack_holder = data;
- frame->fp_offset = (data->fp + data->reloc) - data->stack_base;
- frame->sp_offset = (data->sp + data->reloc) - data->stack_base;
+ frame->fp_offset = stack_top - (data->fp + data->reloc);
+ frame->sp_offset = stack_top - (data->sp + data->reloc);
frame->ip = data->ra;
return 1;